Windows 10 disappointed me again today–my Realtek audio drivers suddenly stopped to work simply after a reboot. All I have now is mysterious "Driver is not signed" error. I tried to remove the unsigned driver (which is portcls.sys by the way) and run sfc /scannow to repair the corrupted file. Did not work. A dism repair worked, but that did not help to solve the sfc issues.
I then made a stupid mistake–I deleted the drivers entirely, a.k.a. all relevant files in C:\WINDOWS\INF, C:\WINDOWS\System32\drivers and most importantly, C:\WINDOWS\System32\drivers\DriverStore. After that I run sfc again and it still does not work!
After cursing Microsoft for making such a silly system repair utility, I return to try to manually diagnose the issue. I first manually copied back all files to INF and drivers, but the driver installations still did not go through. I then try putting back the DriverStore folders–then I found out that I completely forgot their proper names!
Normal Windows Event Viewer only shows a 0x2 error code, so I googled tons of pages to find the location of a proper setup log. It was two hours later that I found the location: C:\Windows\Inf\setupapi.dev.log
After that things went smoothly. You just need to search for Error 2 in the log, and the proper path revealed itself.
!!! flq: Source Media: SPFQOPERATION_ABORT (C:\Windows\System32\DriverStore\FileRepository\wdmaudio.inf_amd64_179dade7dec66387\drmk.sys).
!!! flq: Error 2: The system cannot find the file specified.
!!! flq: FileQueueCommit aborting!
!!! flq: Error 2: The system cannot find the file specified.Now you just need to copy the directory in WinSxS to the DriverStore and rename. After that the audio drivers are finally back working.