CompatTelRunner.exe is a process which is used to upgrade your system to the latest OS version or other Service Pack upgrades. It is also used to perform diagnostics on your computer to determine if there is the possibility of compatibility issues and collects program telemetry information if opted-in to the Microsoft Customer Experience Improvement Program. It allows Microsoft to ensure compatibility when you want to install the latest version of Windows OS.
This process is part of a Windows Update, specifically the KB2977759 one, which stands as the Compatibility update for Windows 7 RTM (Release to Manufacturer). The update is one of the many that serve as a preparation to upgrade to the latest OS version, and will
This process takes up storage bandwidth which may slow down your PC, and you will most likely want to get rid of it. Users complained of multiple CompatTellRunner.exe files showing up in the Task Manager consuming CPU and Disk Usage.
Though this process isn’t really necessary and can be deleted BUT if you do want Microsoft to diagnose your system by itself and run the compatiability checks, then let it run. This can be a privacy concern for some.
The CompatTelRunner.exe file is located in the System32 folder and is owned by the TrustedInstaller any modifications you try to do to it will be met with an “Access is denied” error, which means that you can’t modify or delete it in any way. This is due to the fact that the process is owned by TrustedInstaller, and everything else only has a Read Only permission over it and you can’t modify it.
There is a solution for the issue, and it involves taking ownership of the process, after which you can delete it without deleting the entire Windows update and save yourself from problems OR you can let the program stay, and just disable Scheduled Tasks which launches the program.
Method 1: Repair Corrupt System Files
Download and run Reimage Plus to scan and repair corrupt/missing files from here, if files are found to be corrupt and missing repair them and then see if the problem persists, if it does, move onto the next Method below.
Method 2: Take ownership of CompatTellRunner.exe, and delete it afterwards
The process is a fairly straightforward one, but make sure not to skip steps and keep in mind that you should be logged in as an administrator. First of all, open your Start menu by pressing the Windows key on your keyboard, or by clicking the Windows icon at the end of the taskbar.
Type compattelrunner.exe in the search box, but don’t open the result, which is a file named compattelrunner, and instead right-click on it and select Open file location from the dropdown menu
OR Hold the Windows Key and Press R. Type C:\Windows\System32 and type CompatTelRunner.exe in the search bar on the top right.
Once inside the folder, right-click the Compattelrunner.exe file within it, and select Properties from the menu. In the window that opens, you will notice a Security tab, select it and click on the Advanced button inside. Once the window opens, find the Owner tab, and select Change owner. This will give you a list of new owners, after which you should select the account you are using, and click Apply. You will be met with a prompt that warns you to close all Properties windows that are currently open in order to change the ownership, so close them.
When you’ve changed the owner of the file, next you should change the permissions. To do that, right-click the Compattelrunner.exe file again, and open Properties. Go to the Security tab and click Advanced once again. Within the window, select Permissions, and from the list that pops out, select the account you are using. You will see a new window with options about the permissions. At the top, under the Allow column, select Full Control and click Apply.
When you’re done with this, you are the owner of the file, not TrustedInstaller, and you have full control over it, meaning you can delete it without being met with the Access is denied error. Feel free to do so, and you won’t see it taking over much needed resources from your system.
While there are some solutions you might run into that will tell you to delete the entire update, KB2977759, doing so is not a smart idea as this will mess with the entire schedule of Windows Updates, and you might have bigger issues in the future. Follow the aforementioned steps to safely delete the file and you will have your computer running again in no time.
Method 3: Disable CompatTelTunner.exe from Task Scheduler
Hold the Windows Key and Press R. Type taskschd.msc and Click OK.
Expand Task Scheduler Library -> Microsoft -> Windows -> Application Experience
Right click on any of the tasks listed as Microsoft Compatibility Appraiser and choose Disable.