Some users that have previously configured their computers to dual-boot Windows and Linux distributions (most commonly with Ubuntu) are reporting that their PC is entering Grub Rescue Mode and displaying the error No Such Partition – Grub Rescue.
After investigating this particular issue thoroughly, it turns out that there are several different situations that might trigger the apparition of this issue. Here’s a list of potential culprits that might be responsible for this issue:
- GRUB Bootloader is Corrupted or Deleted – If you are seeing this error due to some type of corrupted data associated with the GRUP Bootloader or after you have unwillingly deleted data associated with it, you can fix the issue by manually reconfiguring the utility to boot using the correct files.
- The bootloader is Misconfigured or Corrupted – Since this issue can also occur due to misconfigured or corrupted BCD data, you should be able to fix the issue by rebuilding the Boot Configuration data from an elevated Command Prompt.
- Current Boot Configuration is inconsistent – In case the issue is being caused by bad data that’s being fed into the GRUB bootloader, you can potentially fix the issue by using a Registry Backup to restore your computer back to a good configuration.
Now that you know every potential culprit, here’s a list of methods that other affected users have successfully used to fix the issue and prevent their computer from booting into Grub rescue mode:
Method 1: Manually Reconfigure GRUB Bootloader
By far, the most effective fix and the one you should start with since it’s the least destructive is to manually reconfigure the GRUB bootloader and make sure that the primary OS is prioritized.
Several affected users have confirmed that they finally managed to bypass the GRUB rescue state by following a set of instructions designed to manually reconfigure the GRUP Bootloader to prioritize the main OS.
If this scenario is applicable, follow the instructions below to do so directly via the GRUB Rescue menu:
- Once your PC enters GRUB Rescue Mode, type the following command and press Enter to get an overview of all your available partitions:
- After you do this, you should get an overview of all partitions that you currently have on your primary disk. At this point, you need to make sure that you select the primary OS. In our case, the correct partition is (hd0,msdos2), so we used the following command to interrogate the partition:
ls (hd0, msdos2)
Note: Make sure to replace the partition with the correct example in your case. If you get a message saying something like ‘File System is ext2 or ext3‘, you have correctly identified the partition that holds your primary OS.
Note 2: If you interrogate a partition and you get the message ‘Filesystem is unknown‘, you didn’t select the correct partition.
- Once the correct partition is selected, type the ‘set‘ and press Enter to interrogate and get a definitive listing of your main partition.
- Next, type the following commands and press Enter after each command to change the priority of GRUB Bootloader to the correct one:
set boot = (hd0, msdos5) set prefix=(hd0, msdos5)/boot/grub insmod normal normal
- After you input the final command, you’ll be taken to the main GNU Grub menu. Once you get to this screen, simply select the OS that you want to boot from and press Enter.
In case this method didn’t work for you and the booting sequence eventually boots in the same No Such Partition -Grub Rescue error, move back to the next potential fix below.
Method 2: Rebuilding the Boot Configuration Data files (BCD)
If the first method didn’t work for you, the next step would be to use the Boot Configuration Data (BCD) utility to locate the Windows installation files on all disks and add them back to the boot list so that the booting sequence can locate it during startup.
This method was successfully used by a lot of users that were previously dealing with No Such Partition – Grub Rescue error. Rebuilding the BCD file clusters successfully allowed them to dual-boot normally without being forced into the GRUP Rescue menu.
IMPORTANT: This method will require you to plug in a compatible installation Windows installation media. If you don’t have one at the ready, you can create the Windows installation media from scratch and load it on a USB drive.
Once you meet all requirements, follow the instructions below:
- Plug-in the USB stick containing the installation media and start your computer normally via the power button.
- Access the Setup key by pressing the correspondent button depending on your motherboard manufacturer.
Note: The setup key will be different from manufacturer to manufacturer. Most commonly the Setup key is either one of the F keys (F2, F4, F6, F8), the Esc key, or the Del key (on Del computers/laptops). If you’re having trouble accessing the Setup menu, search online for specific instructions on accessing it.
- Once you’re inside the Setup menu, access the Boot tab and make sure to set the USB stick containing the installation media as Boot Option #1.
- Save the changes, then restart and allow your computer to boot from the installation media and wait for the installation files to load.
- Once you get to the first page, click on Next, then click on Repair your computer from the bottom-right corner of the screen.
- Next, wait for the Recovery menu to load, then select Troubleshoot and click on Command Prompt from the list of available options:
Note: On certain Windows 10 versions, you might also be able to boot from the Recovery menu by forcing 3 consecutive system interruptions during the startup procedure.
- Once you’re inside the elevated Command Prompt, type the following command and press Enter to fix the MBR dependencies associated with your Windows installation:
- Once the command is processed successfully, type the following commands and press Enter to fix the Boot Configuration Data associated with your Windows installation:
Note: If you get the ‘Access is denied’ error while inputting one of the 2 commands above, follow these instructions to fix the bootrec access problem.
- Next, type the following command and press Enter to scan all your disks for the Windows installation media:
Note: This operation might take some time depending on the size of your partitions. Don’t close this window until the operation is complete.
- If the operation is completed successfully, type the following command to effectively rebuild the BCD configuration data:
- When asked to confirm, type Y and press Enter to confirm and start the operation.
- Finally, type ‘exit’ and press enter to effectively leave the elevated CMD prompt and allow your Windows to boot normally.
In case the end result is the same (the boot attempt ends with the same No Such Partition error), move down to the next method below.
Method 3: Using the Registry Backup to Restore the last good Configuration
If none of the methods above have worked for you, you might be able to fix the current configuration with the last known good backup that should allow you to dual boot without issues.
Doing this will require you to use the Advanced Options menu to open an elevated Command Prompt and run a series of commands that will allow you to boot using the last known good configuration.
This method was reportedly used successfully by a lot of users dealing with the No Such Partition -Grub Rescue error.
In order to use the Registry Backup to restore the last known good configuration, follow the instructions below:
- Insert a compatible Windows installation media and boot from it by pressing any key when prompted to do so.
Note: If you don’t have a compatible installation media or your system doesn’t boot from it, follow steps 1 to 4 from Method 2.
- Once you manage to successfully boot from the installation media, click on Repair your computer from the bottom-left corner of the screen.
- Once you’re finally inside the Advanced Recovery menu, click on Troubleshoot, then click on Command Prompt from the list of available Options.
- Once you are inside the elevated Command prompt, type ‘C:‘ and press enter to access the partition where you installed Windows. If you installed Windows on a different partition, replace the letter accordingly.
- Next, type ‘dir‘ and press Enter to access the root location of your OS drive.
Note: It’s recommended to back up the current registry before going forward. To do this, input the following command and press Enter after each command:
cd \windows\system32\config MD backup copy *.* backup
- Next, type the following commands and press Enter to access the last known good configuration and modify the default behavior to boot from it:
CD regback copy *.* ..
- When prompted by the prompt, press A and hit Enter once again.
- Finally, type exit and press Enter to exit and boot normally. This should take you to the main GRUP menu where you should be able to dual boot as you see fit.