Hi i'm Timon and i'm glad to help you.
You probably use this KB:
https://support.microsoft.com/help/971058/how-d...
If yes, this KB might contain an error, as the entry "Application Data" is a junction that actually points back at C:\ProgramData.
The folder you're looking for is here:
C:\ProgramData\Microsoft\Network\Downloader
So the right command might be:
del "%ALLUSERSPROFILE%\Microsoft\Network\Downloader\qmgr*.dat