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.

taskschd.msc

Run as Administrator.

Expand Task Scheduler Library -> Microsoft -> Windows -> Application Experience

Right click on any of the tasks listed as Microsoft Compatibility Appraiser and choose Disable.