SupportAssisst Takes Too Much Time In Clean Files

My recommendation is to use first the Windows specific Disk cleanup tool, see  https://support.microsoft.com/en-gb/help/4026616/windows-10-disk-cleanup  With it you can also select to clean up the old windows version files, if you do not plan to revert to a previous version or build of Windows 10. After that cleanup also the SupportAssist cleaning is much faster.

I am personally against using cleanup tools different from the Windows ones, the risk is always high that files used by Windows are deleted by mistake. Last week, after a SupportAssist run on a XPS 13 9360 that we have at home , the list of the Windows installed updates also disappeared. Not a big issue, but this was not expected !

- Note: I am a Dell user