On my machine :-( Windows Defender stop working and on Event log I found this:
Activation of app Microsoft.Windows.SecHealthUI_cw5n1h2txyewy!SecHealthUI failed with error: The remote procedure call failed. See the Microsoft-Windows-TWinUI/Operational log for additional information
I started my troubleshooting running System File Checker.
Open CMD as Administrator:
The results of SFC can be these:
– Windows did not find any integrity violations (a good thing)
– Windows Resource Protection found corrupt files and repaired them (a good thing)
– Windows Resource Protection found corrupt files but was unable to fix some (or all) of them (not a good thing)
I was on third option :-(
If you get this message like me, run DISM as described below:
DISM /Online /Cleanup-Image /RestoreHealth
If the repair is successful you may want to re-run SFC just to check.
Unfortunately I get the error message “cannot find source files”.
Windows Installation ISO is then necessary (same build of installed OS). Mount the ISO file and rerun the command specifying where it is located with the below command:
DISM /Online /Cleanup-Image /RestoreHealth /source:X:\Sources\Install.wim
Where “X” is the drive letter where the ISO is located.