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How to fix error 0xc000021a in Windows 8 and 10

Windows 8/10 had a number of issues at the time when it was first released. After a while, when Microsoft started pushing updates, some errors were solved but there were a plenty of them which weren’t. One of those errors is associated with the hex code 0xc000021a.

It states that Your PC ran into a problem and needs to restart. This error appears inside a blue screen of death. So, it may have some serious issues damaging the internal structure of Windows OS. This error also persists even after restarting the PC. Performing a system restore also doesn’t work. So, you would definitely want to know the reason behind this hilarious error message.

Reasons Behind the Error 0Xc000021A:

This issue arises when Windows is updated. So, after the update, it doesn’t boot to Windows and displays this blue screen of death along with error. There are two files that are the major cause of this error to appear. These files are listed below.

  • winlogon.exe: As the name of the file represents, this file is responsible for the login and logout operations inside Windows. This file can be damaged due to mismatch of System Files or 3rd party softwares. If this file gets damaged, then this error causes the PC to boot to the Windows Login.
  • csrss.exe: The second file causing this error is Csrss.exe. This .exe file belongs to Microsoft server or client. So, this file can also be damaged resulting this error.

0xc00021a

Solutions to Fix the Error 0Xc000021A:

There are a number of solutions to fix this error. Just follow the instruction properly.

Method # 1: Repair Corrupt System Files

Download and run Reimage Plus by clicking here to scan for corrupt files, if corrupt and missing files are found, repair them.

Method # 2: Booting Windows Manually

In order to resolve this problem, you have to boot Windows manually. Booting the Windows in safe mode wouldn’t more in most cases. So, you have to boot it using force drivers to have signature disabled option available inside Advanced Boot Options. To access this option, follow the steps below.

1. Restart the PC from Windows holding the Shift key and clicking on the Restart. If you can’t access the Restart option on your Windows, then you might need to boot through a Windows bootable USB.

0xc00021a-1

2. It will take you to an option screen. Select Troubleshoot to access the advance tools.

0xc00021a-2

3. From the next screen, choose the Advanced option.

0xc00021a-3

4. On the next screen, you will see a plenty of options. All you need to do is to click on Startup Settings as shown in the picture below.

0xc00021a-4

5. On the startup screen, there would be a number of options to select from. Press F7 labeled as Disable driver signature enforcement.

0xc00021a-5

PRO TIP: If the issue is with your computer or a laptop/notebook you should try using the Reimage Plus Software which can scan the repositories and replace corrupt and missing files. This works in most cases, where the issue is originated due to a system corruption. You can download Reimage Plus by Clicking Here

Your PC would restart with the option you selected and now, you can tweak your PC using different options.

Method # 3: Fix the Issue using SFC Scan

If the above mentioned method doesn’t solve your issue, you can use System File Checker Scan in order to resolve issues related to corrupted files causing this error. Follow this link to run a full SFC scan on your PC.

Method # 4: Reset the computer’s BIOS

Many users affected by this issue have reported success with resetting their computers’ BIOS. A computer’s BIOS can be reset by simply removing the CMOS battery from its motherboard for a couple of minutes, although this trick doesn’t work with laptops as their motherboards are not readily accessible. In order to reset your computer’s BIOS, you need to:

  1. Shut the computer down.
  2. Remove any and all power cables from the computer, making sure that the computer’s access to electricity is completely cut off.
  3. Pry open the computer’s chassis.
  4. Locate the computer’s CMOS battery (it will be found somewhere on the computer’s motherboard) and remove
  5. Wait for around 1-2 minutes.
  6. Replace the battery once you have waited for long enough.
  7. Put the computer’s casing back together.
  8. Start the computer up and check to see whether or not it successfully boots into Windows.

Method # 5: Replace any and all corrupted registry hive files with backups

Your computer may be affected by this issue because Windows tries to access essential registry hive files when it boots up (like it is supposed to do) but is unable to access them because they have been damaged or corrupted. If that is the case, replacing any and all corrupted registry hive files with their backups should fix the issue. However, since your computer won’t boot up, you can’t replace the damaged registry have files via the File Explorer – you are going to have to do so using a Command Prompt in the Windows Recovery Environment.

In order to get into the Windows Recovery Environment, though, you are going to need a Windows installation USB or disc containing the installation files for the same version of Windows as the one that’s currently installed on your computer. In order to use this method to try and get fix this issue, you need to:

  1. Insert the Windows installation disc or USB into the affected computer and restart
  2. As soon as the computer starts booting up, get into its BIOS settings and configure the computer’s boot order to boot from the installation media instead of its HDD/SSD. Instructions for getting into the computer’s BIOS will vary from one computer to the other but will almost always be found at the first screen you see when the computer boots up.
  3. Save the changes and exit the BIOS
  4. If prompted to do so, press any key to boot from the installation media.
  5. Select your language, time zone and keyboard layout preferences and then click on Next.
  6. When you reach a window with an Install now button at its center, look for and click on Repair your computer in the bottom left corner of the window.

You should now arrive at the Startup Options screen. Once you are here, you need to:

  1. Click on Troubleshoot > Advanced options.
  2. Click on Command Prompt, and a Command Prompt will be launched.
  3. Type c: into the Command prompt and press Enter. If Windows is installed on a partition of your computer’s HDD/SSD other than the C drive, replace c with the driver letter that corresponds to the partition of the HDD/SSD that Windows is installed in.
  4. Type cd windows\system32\config into the Command Prompt and press Enter.
  5. Type dir into the Command Prompt and press Enter. The Command Prompt will now display all the files and folders present in the directory.
  6. One by one, for each file (not folder, only file) present in the directory, type the ren (File Name) (File Name).old command and press Enter.

For example: Type in ren SYSTEM SYSTEM.old for the SYSTEM file in the directory, and ren SECURITY SECURITY.old for the SECURITY file in the directory.

 

  1. Once you have renamed each of the files in the directory (creating backups of each of them), type cd RegBack into the Command Prompt and press Enter.
  2. Type dir into the Command Prompt and press Enter. You will now see all of the files and folders present in this directory.
  3. Now type the following commands one by one:

copy /Y SOFTWARE

copy /Y SAM

copy /Y SYSTEM

and any other folder that was renamed, we now need to put the registry hives back for the folders we renamed.

Once done, close the Command Prompt, get out of the Windows Recovery Environment, by typing EXIT and press ENTER remove the Windows installation media and restart the computer to see whether or not it is able to successfully boot up without running into the 0xc000021a screen.

PRO TIP: If the issue is with your computer or a laptop/notebook you should try using the Reimage Plus Software which can scan the repositories and replace corrupt and missing files. This works in most cases, where the issue is originated due to a system corruption. You can download Reimage Plus by Clicking Here

RECOMMENDED: Click here to fix Windows errors and optimize system performance

About Kevin Arrows

Hi! I'm Kevin. Thank you for reading the article above. I am a certified MCTS (Microsoft Certified Technology Specialist) with over 10 years of experience. I love to address tech issues, and write tech how-to's in a way that it can be followed by everyone.
  • Can you try booting with force drivers to have signature disabled; then check on the manufacturer’s site to see if there are drives available for your OS (10 or 8) which ever you’re using. Thanks

  • Are you able to get to the login window where you enter your password?

  • pannna

    Came across this problem after upgrading to win 10 from 8. And after a few more installations (office, printer, etc).
    It first asked for Bit locker key and after entering the key it went into 0xc000021a loops.
    Am trying different things mentioned online (sfc scan, command prompt> DISM move, reset, image recovery, manual booting).

    However no luck so far 🙁

    • Looks like you will need to do a clean re-install.

  • pierre

    Neither of the two proposed solutions work. I’ve tried everything I can think of and remain in the BSOD loop.

    • Are you able to boot into safe mode if you start with the installation media? If this is a desktop, i’d suggest removing the cd/dvd drive, and the wi-fi card/adapter it it’s external. Once you boot into the computer, there will be dmp file in C:windowsminidump which will have more details about the BSOD which we can diagnose. You’ll need to upload it to eQuestions.net

  • Ron G

    This worked for me. It occurred after I have had Win10 running fine since it was released five months ago. Then, AVG did an update, and that’s what screwed it up. By following the F7 technique above, I got mine working find again. Also, WIn10 was attempting to update at the same time as AVG, so that may have caused it. It is fine now. System Restore did nothing.

  • Please confirm if hardware signatures were disabled correctly? Thanks

    • Samuel W. Coleman

      I tries te F7 technique several times but no luck my laptop is normally windows 7 but upgraded it to win 10

      • You can use the installation disc to get to the advanced menu.

  • Meisha Flemmins

    this helped me and was much more thorough.

  • Mohd Salleh

    Hello, I have tried the first method. Unfortunately, it does not seem to work at all. Once I pressed f7 my pc restarted but the problem still remains.

    • Can you ask this as a new question on eQuestions.net/ask so i can assist you directly.

    • Rasmus

      It’s the same I have, did you find out what it was?

      • If you guys can provide detailed description – i’ll be able to assist.

  • Mike James

    Hello Kevin.. Running Windows 10. I have this error problem. I am thinking of loading Windows 7 from disc and then, try and load 10 again… Is this doable? Will the “problem Windows 10” allow this? Thanks for your help

    • I am sure that a clean installation will fix it. However, since it has already been upgraded, you can try a clean install of Windows 10. If you can boot to advanced mode, then use the features listed to this other create a bootable windows 10 disc using rufus, and then boot from it to re-install. When you do this, you will not have to re-enter license keys since it is already updated. http://appuals.com/create-windows-10-bootable-usb-with-rufus/ – Do let me know the results as i am keeping track of this issue to help others by noting down solutions that worked.

      • Mike James

        Thank-you

        • Make sure you take a full backup of your important data before performing a clean install.

  • frank discussion

    #1 did not work 4 me. #2 resulted in “Windows Resource Protection could not perform the requested operation.”
    Previously, I reset the PC. Then, I found where restoration is off by default(!), so turned it on. The next restart, it happened again, and the fourth (the oldest) restore worked. But, here we are again! As I’ve just moved, finding install discs is a PITA. Thanks a bunch, Microsoft…NOT!!!
    Even worse: now there are no System Restore points, either. Not just about this “not ready for prime time” case, but Microsoft should spin off it’s OS division into a separate company, maybe their overall reliability as well as simplicity would both improve.

    • Have you tried booting into safe mode?

  • Dustin

    How are we supposed to follow a link to run a scan on a PC that won’t boot

    • You will need to create installation media for your Operating System to boot from it. BUT what exactly is the issue you’re having?

  • Do you have another computer to create installation media?

    • frank discussion

      Yes. I just borrowed one. However, I have never created installation media. I just moved, too, so my Windows 7 disc is buried somewhere as well.

      • You can download Windows 7 ISO. You can also download Windows 10 to repair/run. BUT the error mentioned in this guide is for Windows 8 and 10. Can you open a new with your exact issue on eQuestions.net/ask – i will be able to assist you one to one.

  • Please submit this as a new question on equestions.net so i can assist you directly; and if needed connect remotely to check.

  • David L

    Hello, I am getting this same error code, the only thing that the computer will do is restart over and over, it will not allow me to get into anything else, restore mode will not come on either, it shows on the screen for a brief second, then the blue screen shows up again, and restarts. it will not even let me do anything with boot cd, its like its not even there.
    please help

    • Are you able to get into advanced options?

  • Lynn Pinti-Gomez

    I am having this problem as well, and I own a Cyber Cafe. The problem is with my master computer and the only way of fixing it was to refresh/reboot. I have done this 4 times over the past month (very frustrating). On the last time, I used Method #1, which worked. My question is this….if my computer shuts off unexpectedly or I do a restart, this is when I get the error code. If I shut down, the computer is fine when I turn it back on. If I did Method #1, has the problem been permanently fixed? or will this error come up again upon a restart? (I’m afraid to try) Thank you.

    • I suggest you try to find out and turn off windows updates.

      • Lynn Marie Pinti-Gomez

        I just had this problem come up again, even after I believed I turned off updates….how can I permanently turn off updates or Permanently repair this issue. I can’t keep reinstalling Windows every couple of weeks! Help me please!

        • Go to services.msc, locate Windows Update service, right click on it and choose properties, and set it to disabled.

  • Are you able to reset windows 10, when you go to reset it from the advanced options, you have the option to keep files or remove files. If i were you and the files weren’t important for me, then i would remove them and do a reinstall.

    • Jessica

      Okay. I have most of it saved on different external drives, but wanted to check and make sure before everything disappeared.

      • If it is saved, then you’re good to with the reset option.

  • Mark Whitbread

    So on trying this I just get the blue screen again saying it needs to restart after gathering error data. I’m being told now I will probably have to uninstall and reinstall losing files. Any other successes, I’ll be watching.

    • If you can boot to safe mode, then you copy the files over to the USB. You can also attempt a system restore to a point when the system was actually working without the error through advanced mode.

  • Alen Brandizzi

    o have stucked 5 days with this problem of winload.efi error or error 0xc000021a and tried rapidly this solution without sucess, but today i did it step by step
    1) re-start pressing shit button. (and Os selection show up)
    2) using tab in second screen to select other options of boot
    3) disabling driver signature.
    4) my windows 10 start again.
    5 ) im doing now an sfc/ scannow to check erros in admin mode.

    thanks . i have a Sony vaio without recovery working

    • In the Bios settings -> Boot -> Secure boot options

      => Set Secure Boot option to “Disabled”

      • Alen Brandizzi

        doesnt work to me

        • Okay. Do SFC Scan and upload CBS.LOG file to equestions.net/ask in a new question so i can assist.

  • Are you able to login before the error?

    • Michel Hayek

      No i cant do anything

      • please submit question on equestions.net

  • Uil_en_spiegel

    At my last automatic updates with Win 10 I got a blue screen of death along with error. The killer was error 0xc000021A. After consulting a Pc nerd I was adviced to begin browsing and to search for a solution. At last I came on this page. In a minimum of time I got the device back on te rails again. The bug was fixed fast and well. Btw. at this same moment my mouse gave up, dead. I was mislead and confused by it , so I thought after the correction I had done wrong something but ….a new mouse showed me everything was OK. Tx Kevin for your support with this bothersome problem.

  • You will need to trace it with trial and error which can be a lengthy process. You can wait a couple of months and re-run updates, hopefully MS will issue a patch or another update to fix it. Until then, just use a good antivirus and a malware software to stay protected. If this error comes back without updates, then that would indicate that it’s not the update but a program changing settings. We’ll check that out when it happens.

    • Lynn Marie Pinti-Gomez

      Kevin…Thank you, thank you, thank you. You have been a LOT of help in this matter. I am not computer savvy, that’s my brother…when I asked him about this, his response was “I never upgraded to Windows 10, so you are on your own!” Needless to say, I have been upset over this whole ordeal since it started. I am hoping that it is caused by one of the updates and it can be fixed in the future. Lets cross our fingers that I won’t be talking to you too soon that it happened again. Thank you again for your assistance!

  • Pavan

    Even i got the same problem .I did all the steps as u said .Its restarting but again got the problem wat should i do ?

  • Pavan

    Even i got the same problem .I did all the steps as u said .Its restarting but again got the problem wat should i do ?

    • If this solution did not work, then you would need to do a clean install.

  • Karim

    I tried both solutions but don’t work for me .. I’ve to install fresh copy of windows every day! What may be the problem?

    • After installing the fresh copy, disable windows updates.

  • patti

    I need help. Got the blue screen. (then before i checked here) i tried a system reset. Now it tried to back up files- it stopped and a screen came up that said files could not be read it left a screen that asked me to terminate???? I am a computer dummy, please help.

    • You will need to reinstall Windows

  • Shena May Ria

    Hi. Is it normal that after preasing F7 the screen turned black and until now it’s black. Please help. My laptop is not turning on now after pressing F7.

    • No, it is not normal for it to go black. Try rebooting it.

      • Shena May Ria

        Should i repeat the process sir?

      • Shena May Ria

        Should fn button be pressed together with the F7 button? I can’t select F7 alone.

        • You cannot use it with Fn. Try pressing 7 only.

          • Shena May Ria

            It don’t work with F7 only. I have a x200m asus notebook and i don’t think pressing Fs alone would
            work.

          • try pressing number 7 key only.

  • shailendra

    i had tried both the method but it is still not working

    • I beleive the solution to fix issue in your case would be to do a factory reset or a clean reinstall of Windows 10.

  • You have no errors when your PC Can’t turn on, you need to address the “pc turning on” issue first before you get to this .

  • John Decker

    How exactly do i do a complete reinstall – I’ve tried the above options and others and can’t get anything going – i downloaded the windows 10 to a disc I think but the computer wouldn’t boot from the disc – but then again – i’m clueless to some of the in depth details – any set of instructions on exactly how to do a complete clean reinstall? thanks

    • Did you extract and burn the iso file to the disc?

      • John Decker

        i don’t think i did it correctly – can you help me out on the process?

        • 1. Download the Windows 10 ISO File.
          2. The download Rufus

          OR Download Media Tool from Microsoft site, download the ISO and then burn it to the usb.

          3. Burn the ISO to the USB or Disc.
          4. Boot your system to BIOS and change the boot order to the boot media.

          If you have access to a usb and a 2nd computer, i can remotely do this for you.

          • John Decker

            i am on my laptop at work now – that would be awesome, i’d appreciate it very much

          • when can we connect

          • John Decker

            sorry didn’t get a chance to get back to you – got busy yesterday
            i’ll try to download it this morning

          • sure.

          • John Decker

            i think i got it done correctly – i’ll probably see if i can use the disc tonight and see if it works – thanks for the help – i’ll post up results

          • thanks

          • John Decker

            the iso disc worked – took a few hours for everything to work through – but so far after spending several hours putting software back on – moving files where I want them the computer and OS seem to be working fine – very time consuming – for those contemplating a fresh new clean install – all your files will be saved in a “windows.old” folder so you won’t lose anything, at least I didn’t

          • thanks for letting me know.

  • LaLa

    I have a Lenovo Laptop, Windows 10. I TRIED this fix but it still takes me back to the error screen. I also tried to do this but doing Safe mode with the Command Prompt so I can do the scan but it stills goes right back to error screen. PLEASE HELP.

    • You will have to reinstall Windows.

  • Dulal Nandy

    my keyboard doesnt seem to function and i am unable to select f7 from startup settings. pl require urgent help

  • Dulal Nandy

    neither enter key works which will take me back to os as listed. unable to do anything with the pc. data inside which is urgently reqd

  • Dulal Nandy

    when i go for sfc scan gives me a message system repair pending to go back restart and run sfc again. the keyboard works now and accepts text in command prompt. need to recover the system urgent. I tried to reinstall windows from installation CD but it doesnt go to the mode as keyboard now aagain doesnt respond. it responded only in command prompt. pl help

    • Go to bios, and reset it to defaults. Then try reinstalling via USB.

  • Please reset your bios to defaults, and then test.

  • DR

    This information saved me!! Clear and easy to understand with the pictures of the steps! Thank you!

  • Still doesn’t help me:

    The problem goes like this:

    A
    1.) Windows update runs automatically and without any ability to pick and choose what to update;
    2.) Windows boots, dies on blue screen, saying error “0xc000021a”
    3.) Computer restarts, then the troubleshooting options is taken, this is followed, and restart with driver signature disabled.
    4.) Windows crashes again at boot. Blue screen, saying error “0xc000021a”

    B
    1.) I now use system restore instead from trouble shooting.
    2.) System restore works, and it was back before the auto updates are installed
    3.) but since it’s windows forces auto updates and installs all updates without you having the ability to pick and choose – it installs the same thing that crashed the laptop in the first place.
    4.) After enjoying the short life of your OS, you restart, to find windows is auto updating again.
    5.) Windows boots, dies on blue screen, saying error “0xc000021a”
    6.) Repeat B.1 and loop this process.

    • Do a system restore whilst the PC is disconnected from the internet. After the system restore, go to Windows Updates, and change settings to choose what to install.

      • I actually found a fix somewhere else where it instructed me to download this windows 10 windows update-picker, where you can pick and choose which update you want. It was developed by Microsoft. It’s funny that this feature is just some third-party download that is not included build in to windows 10. This add-on for windows update just helped me a lot. What a nonsense from Microsoft as if they realised their fault later on.

        • I’d like to update my guide with your fix. How did you conclude that you needed to hide / uninstall an update? If you can send me a detailed guide, that will be helpful.

  • Kacper Kaliszczak

    Will the first solution delete all files or kep them?

    • no. what makes you think it will?

  • Bharat Mittal

    ok…. i read various methods and solution to start my pc from solutions provided by you
    and i tried all of them
    1) restarting pc is not helping, then
    2) troubleshooting via restore point is not working (system restore is completed to 100% and when it restart the PC, it leads to same error)
    3) i have system recovery but it’s not working
    4) system reset is also not successful
    5) i got your suggestion to change startup setting and i tried one after another, all the option’s from F1 to F10 but all in vain
    6) last option was cmd, but sfc/scannow leads to (when i go for sfc scan gives me a message system repair pending to go back restart and run sfc again) error

    now i left with the option of fresh installation of windows but the problem is that, i had a bootable disk of genuine windows 7 which i upgraded to windows 10 and now i don’t have any bootable disk of win 10 and windows 7 cd is not working over win 10
    plz suggest some solution.

    thanks in advace

    • Greg

      The Win 10 key is in your bios, just install win10 from the free official microsoft ISO and you’ll see your Windows will be activated.

  • a.m

    If I boot my pc will be deleted all my fies.

    • If you reset and choose to delete files, only then they will be deleted.

  • Neha Bagri

    After doing all the steps it is still loading the blue screen. Please help

  • You’ll need to check which drivers are causing it, the blue screen of death would tell the name of the file triggering it. Type that to me here.

  • Mark Molloy

    Hi I’m also receiving this error tried pushing the f7 option it’s not working.

  • are you running windows 10 or windows 8?

    • Ria

      I’m running 10.

  • after performing method 1, without rebooting do a clean boot and then reboot. http://appuals.com/best-guide-how-to-clean-boot-windows-10/

    • Ria

      Thanks i wil go do this step by step. I’ll give feedback soon

    • Ria

      Thanks a lot. This fixed all!!

  • max kid

    It does not give me the option for disabling Driver Signature enforcement it does not even show me the option to enable safe mode. I am on a hp 15 notebook Pc windows 10. I can nor even reach the login screen

    • Which screen are you able to reach?

      • max kid

        I used to be able to reach the advanced options and troubleshooting page. As of later today I am now stuck on a black screen after the windows logo with the words under it

        • Reboot and interrupt 3 times, at the logo screen.
          Make sure no external devices/usbs are connected.

  • I would suggest you do a clean install in this case.

  • Patty

    Hi, I am totally not a computer genius so I have to ask this question, how do I get by the blue screen of death to do these fixes?

    • So when you start it does it goes directly to the error screen?

  • Stephanie

    I can’t get past the blue screen of death step 3 isn’t working and I can’t get past the blue screen to try 1 or 3?? Please help

    • Take all external devices out of your system, reboot the PC three times, and interrupt the 3 reboot times to boot into the advanced mode. Once in advanced mode, disable driver signatures and then try.

  • mr nk

    I tried solution 2 which did not work for me. Please my machine won’t even boot how am I to download and use reimage? I have been without my machine for too long now

    • Tell me what the final screen is that you can get to?

  • I can help you troubleshoot it. Are you able to boot into your Windows or are you presented with this error before you login?

    • christophe cousin

      Hi thank you when i restart it goes directly to repairing your computer then diagnosis then your pc did not start correctly so i go to advance option startup setting and tried all f1 to f7 but does not work back everytime to pc ran into problem collect info then you can restart blue screen flash code and stop code Oxcoooo21a OS 8 OS 10 having this for 4 months and this will be 5th recovery the second for OS10 what shall i do thc

      Note 3 days ago same issue i managed to go back to previuos build ie OS8 it works re upgrade OS10 worked 24h and crash

      • Can you boot into advanced mode, go to Command Prompt and then type the following commands, then do a reboot and test.

        bootrec /fixmbr

        bootrec /fixboot

        bootrec /rebuildbcd

        Disconnect all external devices connected to it.

        • christophe cousin

          I did it it says after typing then enter first one operation completed successfully second one successfully 3rd one litle time scaning all disk for windows installation , sucessfully scanned and total identified Wnidows installation: 0
          Operation complete succesfully so i close the window close the PC and start open direct to your pc ran into problem stop code oxc000021a did it twice…

          • Try the following:

            Step 1: Type
            cd WindowsSystem32Config

            Step 2: Copy

            copy BCD-Template Temp and Press Enter

            copy COMPONENTS Temp and Press Enter

            copy DEFAULT Temp and Press Enter

            copy SAM Temp and Press Enter

            copy SECURITY Temp and Press Enter

            copy SOFTWARE Temp and Press Enter

            copy SYSTEM Temp and Press Enter

            STEP 3

            ren BCD-Template BCD-Template.bak and Press Enter

            ren COMPONENTS COMPONENTS.bak and Press Enter

            ren DEFAULT DEFAULT.bak and Press Enter

            ren SAM SAM.bak and Press Enter

            ren SOFTWARE SOFTWARE.bak and Press Enter

            ren SECURTY SECURITY.bak and Press Enter

            ren SYSTEM SYSTEM.bak and Press Enter

            STEP 4
            copy C:WindowsSystem32ConfigRegbackBCD-Template C:WindowsSystem32ConfigBCD-Template and Press Enter

            copy C:WindowsSystem32ConfigRegbackCOMPONENTS C:WindowsSystem32ConfigCOMPONENTS and Press Enter

            copy C:WindowsSystem32ConfigRegbackDEFAULT C:WindowsSystem32ConfigDEFAULT and Press Enter

            copy C:WindowsSystem32ConfigRegbackSAM C:WindowsSystem32ConfigSAM and Press Enter

            copy C:WindowsSystem32ConfigRegbackSECURITY C:WindowsSystem32ConfigSECURITY and Press Enter

            copy C:WindowsSystem32ConfigRegbackSOFTWARE C:WindowsSystem32ConfigSOFTWARE and Press Enter

            copy C:WindowsSystem32ConfigRegbackSYSTEM C:WindowsSystem32ConfigSYSTEM and Press Enter

            then test, and let me know.

          • Sacha

            Hi, I followed your instructions but windows still failed to boot. My regback folder didn’t contain BCD-Template or COMPONENTS so I copied them from another windows 10 laptop, but it still failed.

          • Have you tried system restore from the advanced options?

        • christophe cousin

          Thx the list is very long am not computer nerd 50yo in your list i do not know what you mean by copy after first step copy from where or what i must write copy then again copy xxxx enter? I am affraid it is going to be back to shop or can we chat line whatsapp? Thx

          • All you need to do is get back to command prompt, and type without thinking. First type STEP 1 commands, then STEP 2 and so on.

  • Vee

    Hi there! This is the first time this issue has happened and I am still unsure how to proceed. The first thing that shows is the black screen with the hp logo and right after it shows the blue screen then returns to the black, then blue and so on. What should I do? Thank you!

    • Reboot the system three times, and before the blue screen appears shut it down using the Power button. The aim is to interrupt the process, such that the Windows should boot into the Advanced Mode. Once it goes to the advanced mode, choose Troubleshoot -> Automatic Repair and repair the system.

  • Juhstn

    Hi, Kevin. I tried all your methods to fix my computer, but they didn’t work. Do you think you can help? Thanks!

    • Can you try the steps i have given to christophe cousin

      • Juhstn

        I’m not sure how to put my computer in advanced mode. It’s already at the blue screen and I can click “Advanced options”. Do I just need to type this in “Command Prompt”?

        bootrec /fixmbr

        bootrec /fixboot

        bootrec /rebuildbcd

        • Click Advanced Options, then choose Troubleshoot and then choose Command Prompt.
          Also tell me if there was an update that was installed before the issue started?

          • Juhstn

            The Windows Anniversary update was installed before this happened, but that was a couple of days before. My screen froze one day so I decided to shut it down and now this is occurring. Anyways, I finished the last command, but by reboot does that mean just press the power button and shut it down? Sorry, I’m really bad at this stuff.

          • press the esc key, and there should be an option to reboot.

          • Juhstn

            I pressed esc and nothing pops up.

          • click the X to cross it out.

          • Juhstn

            I don’t get what you mean by that.

          • Can you take a picture of the screen and attach it here?

          • Juhstn

            Yes

          • There is a red x on the top left of the command prompt, click it and then click “Continue” / exit and continue to Windows 10

          • Juhstn

            It ended up taking me back here. 🙁

          • Go to Advanced Options -> Troubleshoot -> Startup Settings -> Restart
            After it restarts, press 7 (disable driver signature)

          • Juhstn

            It took me back to the same place. 🙁

          • Troubleshoot -> Advanced Options -> System Restore -> Select your User Account -> type the password -> choose a restore point to the time when it was working fine.

          • Juhstn

            “No restore points have been created on your computer’s system drive.” I’m sorry nothing is working. :((

          • Do you see an option in Troubleshoot to Go Back to the Previous Build?

          • Juhstn

            Yes.

          • Juhstn

            I think I remember trying this and it failed, but I’ll try and see.

          • Please try and let me know.

          • Juhstn

            Didn’t work. 🙁

          • Go to command prompt, and do the following:
            Step 1: Type
            cd WindowsSystem32Config

            Step 2: Copy

            copy BCD-Template Temp and Press Enter

            copy COMPONENTS Temp and Press Enter

            copy DEFAULT Temp and Press Enter

            copy SAM Temp and Press Enter

            copy SECURITY Temp and Press Enter

            copy SOFTWARE Temp and Press Enter

            copy SYSTEM Temp and Press Enter

            STEP 3

            ren BCD-Template BCD-Template.bak and Press Enter

            ren COMPONENTS COMPONENTS.bak and Press Enter

            ren DEFAULT DEFAULT.bak and Press Enter

            ren SAM SAM.bak and Press Enter

            ren SOFTWARE SOFTWARE.bak and Press Enter

            ren SECURTY SECURITY.bak and Press Enter

            ren SYSTEM SYSTEM.bak and Press Enter

            STEP 4
            copy C:WindowsSystem32ConfigRegbackBCD-Template C:WindowsSystem32ConfigBCD-Template and Press Enter

            copy C:WindowsSystem32ConfigRegbackCOMPONENTS C:WindowsSystem32ConfigCOMPONENTS and Press Enter

            copy C:WindowsSystem32ConfigRegbackDEFAULT C:WindowsSystem32ConfigDEFAULT and Press Enter

            copy C:WindowsSystem32ConfigRegbackSAM C:WindowsSystem32ConfigSAM and Press Enter

            copy C:WindowsSystem32ConfigRegbackSECURITY C:WindowsSystem32ConfigSECURITY and Press Enter

            copy C:WindowsSystem32ConfigRegbackSOFTWARE C:WindowsSystem32ConfigSOFTWARE and Press Enter

            copy C:WindowsSystem32ConfigRegbackSYSTEM C:WindowsSystem32ConfigSYSTEM and Press Enter

          • Juhstn

            It didn’t work. 🙁

          • You mean, you cannot get to advanced mode?

          • Juhstn

            Ugh sorry I accidentally double posted–said I didn’t post it.
            Anyways, I typed the first command and it says “The system cannot find the path specified.”

          • You will need to create a bootable Windows 10 media, and boot the system using the media. Then repair the system, using the installation disc. See steps here: http://appuals.com/create-windows-10-bootable-usb-with-rufus/

            I will be logging off for today. Let me know how it goes.

          • Juhstn

            I can’t do that. Anyways, I thank you so so so much for giving up your time to help me. I really appreciate that. I’ll figure out a way….hopefully. Once again I can’t thank you enough. 🙂

  • Liam Child

    I was presented with the error code 0xc000021a on my laptop – The blue screen of death comes on to the screen everytime the computer boots up and woldnt allow me back in to windows – i tried using the second step above and it hasnt worked – i have also tried the turn ur computer on and off several times as it boots up . at times the computer will “diagnose” itself and then say “automatic repair” but even after that just takes me straight ack on to the blue screen – i dont know what to do im at the end of my rope HELPPPPP

  • Liam Child

    I was presented with the error code 0xc000021a on my laptop – The blue screen of death comes on to the screen everytime the computer boots up and woldnt allow me back in to windows – i tried using the second step above and it hasnt worked – i have also tried the turn ur computer on and off several times as it boots up . at times the computer will “diagnose” itself and then say “automatic repair” but even after that just takes me straight ack on to the blue screen – i dont know what to do im at the end of my rope HELPPPPP MEEEEEE PLEASEEEEE

    • Could you tell me how it started, what exactly happened?

      • Liam Child

        the computer was on and it froze completely then just crashed

      • Liam Child

        my little sister was using it – the computer lagged and she banged the keyboard but not very hard because it suddenly froze and then it just crashed – ever since its just been a blue screen that will not let me log on

        • Does it gives you an option to go to Advanced Mode?

          • Liam Child

            Sometimes when i turn it on it loads then goes straight to blue screen gives me the error code and tells me that it needs to restart – It does then goes to an automatic repair… diagnosing your pc .. tells me it didnt start properly and gives me the advanced options

          • Liam Child

            Following this it gives the options to continue, turn off pc, use a device or troubleshoot .. when you press troubleshoot it says refresh pc, reset pc or advanced options.

          • Liam Child

            Then its system restore, command prompt, system image recovery, firmware settings, start up repair, start up settings

          • Choose System Restore, and tell me if there is a Restore Point available (for the date when it was working fine)?

          • Liam Child

            says no system restore points have been created on your computer systems drive

          • Do you have any important data on this system? If not, then you can do a reset.

        • Brad Newman

          she slammed on the keyboard which made your hard drive go bad.

  • daniloperetti

    Hi Kevin Arrows,

    Really thank you about this article, it resolved my problem!!!

    I was using months ago a notebook Asus K52F with w10 Windows 10 when it stopped with this 0xc000021a. I began to use Linux Mint Live CD since it (recommended). But today I needed to resolve it when I saw your page. It worked when I did “…you have to boot it using force drivers to have signature disabled option available inside Advanced Boot Options”. It worked like a charm! Automatic I turned off internet wireless after it, see below why.

    I saw to the link https://www.asus.com/us/support/FAQ/1016000
    What I could understand Asus can stop from hibernation/sleep because sometimes after update windows 10 changes Intel Management Engine Interface driver, resulting a a compatibility error. Then it recommended to download and change the driver.

    I will do it. I hope that it can help others

    Bye!

  • Okay, i would suggest that you should do a clean install.

  • It would be best to just do a reinstall.

  • I would suggest you do a reinstall.

  • It would be best to reinstall your windows, speaking from experience if you’ve tried all of the steps mentioned here and the hardware isnt at fault, then reinstalling would be the way to go.

  • You will need to use another PC to download ISO and burn it onto a USB or a disc, and then change boot order from bios to boot from the media (usb or cd) and then do a reinstall. You can use the license keys you have to activate once it is installed.

  • You mean, SSD is not showing up in the boot order?

  • I’d suggest you format this drive, on an other PC by connecting it to the other pc using a disk enclosure and then try installing windows, if the disk is faulty, you will know when you connect it to the other pc.

  • You can use a disk enclosure to copy the data first, and then do a reset.

  • Apologies for the delayed response. What i meant to say is that if you get a Disk Enclosure and copy the data (not clone) to another drive or computer by putting the drive from the computer in question into the enclosure and then once the data is copied, you can then do a clean install.

  • Thanks for the suggestion

  • thanks for the suggestion

  • Benny Boop

    Same issue. cp is not a command on Windows 10 either.

    • use copy command.

    • I’v’e updated the guide.

      • Benny Boop

        Thanks, I’ll try it soon.

  • No, .old is when you rename them

  • bok bok

    windows 7 is the best