This pop up appears randomly when I use my new Win 11 PC.
I have been onto Microsoft Help and they have scanned the PC for missing system files and found that it is ok.
They say it is an issue with Nortons.
I don't use the Citrix workspace app that is involved. But my wife will after I get this (according to Google) bug fixed.
Multiple searches say it is an issue with Nortons
Actually it is there - wasn't in the first place I looked - was further down the list.
Can only find up to Citrix\ICA Client - rest of ctxapclient32.dll is not listed.
I have uninstalled the app and reinstalled from the citrix website, but it did not make a difference.

Curious, do you find 'C:\Program Files (x86)\Citrix\ICA Client\ctxapclient32.dll' on your machine?
````````````````````````````````````````````````````````````
fwiw ~
Nsc.exe: What It Is & How To Fix Nsc.exe Errors
https://malwaretips.com/blogs/nsc-exe/
```````````````````````````````
Community search = Nsc.exe
https://community.norton.com/en/search/site/Nsc.exe
````````````````````````````````````````````````
NSc.exe Error (0x0000142) Posted: 10-Oct-2022
https://community.norton.com/en/forums/nscexe-error-0x0000142
NSc.exe Application Error unable to start
https://community.norton.com/en/forums/nscexe-application-error-unable-start
NSc.exe Error 0xc0000142
https://community.norton.com/en/forums/nscexe-error-0xc0000142
````````````````````````````````````
BigStevie:
Multiple searches say it is an issue with Nortons
Run Norton Autofix to detect and repair common problems
https://support.norton.com/sp/en/us/home/current/solutions/v15756942
Please review: How To - Contact Norton Official Support