Disk Cleanup and Windows 10 boot Blue Screen / Critical Service Failed – Disable drivers signature enforcement, Unsigned Drivers

Quick Post & surprising follow up to the workaround for Windows 10 Critical Service Failed Boot Blue Screen (Recovering from Windows 10 boot Blue Screen, Critical Service Failed, Disable drivers signature enforcement, Unsigned Drivers)

*update 2017-05-19, found this thread on reddit with a safer fix/workaround: seems installing the new Windows creators update fixes the issue, so would advise for that first!*

Just received great feedback/hint from Eric E Swanson (see here) -while applying the described workaround successfully  (great to know!). From his reply:

“…This problem happened to me when I used the Disk Cleanup utility and removed Old Windows installations and/or Temporary Windows Update files (not sure on the exact verbage, but it was part of the list when you click on System clean up)…”

I did a few tests on my own (yes, I had that problematic folder properly backed up, and a full OS partition image also, just in case) and…

Turns out a surprising operation that can cause the Windows Critical Service Failed boot BlueScreens is really…. Windows Disk Cleanup Tool…


Just tested and really something strange is happening with Disk Cleanup. First time I ran it, left the default few options (sorry didn’t proper screenshot that), confirm delete, wait a few seconds, nothing. Everything still the same on C:\Windows\System32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE} 4.586 files from my last restore (note: these are driver signatures that Windows checks if drivers are properly signed)


Ok, I don’t give up easily…. 2nd run,this time selecting Clean System Files, then leaving the only default option checked, Temporary  Files. Also strange that it mentioned ~20GB of cleaning (that folder is around ~100MB total)


But this time a few files were actually removed from C:\Windows\System32\CatRoot\{F750E6C3-38EE-11D1-85E5-00C04FC295EE} . 


Ok a few files removed… strange, so ran it again, same options, selecting Clean System Files, then Temporary Files. Also strange that now seems to mark only ~15GB to “clean”. Swear probably it’s the last I use this tool…..


So, this time, after cleanup, these were the only files left: (67 files only!) Almost the entire driver signature folder completely removed:


So, testing the boot right? Back to the old boot BSOD/Critical Service Again (at least that makes sense!). Now much quicker to recover, as described in previous post, just pasted the files again from a backup folder (after disable boot option, drivers signature enforcement).

Boot again with the folder recovered, no more blue screens or issues with unsigned drivers!

Even strangest, tried several times after that, even with a few reboots, can’t seem to replicate it now using Disk Cleanup. Folder steady at the 4.586 files.

After all this, also strange than I got now ~5 GB (keeps changing?) yet to be cleaned no matter how many times I try. Meantime, I can confirm I have around more ~15GB free space on the win partition. What files has cleanup removed? Don’t have a clue and it’s kinda freaking me out….. tool from hell. Smile (which btw remind me the BOFH immortal words… “Well, let’s see, you have 4 Meg available" …)



Searching online there are several help requests regarding this kind of Blue Screen , and even a few mentioning Disk Cleanup as a possible cause. (see below)

Didn’t found any official/tek details info from msft , seems lacking proper awareness & follow-up from msft support teams honestly (yes, if not already, someone should really be looking into this).

How can such annoying, frustrating boot Blue Screen  keep appearing online and being so difficult for users getting proper solution beyond the typical- format & start again? (seems also something is lacking on the startup logs/troubleshoot process, are we not in the age of big data?…)

So, hope this helps,(helped two of us any way Smile )


Similar issues mentioned online

Reddit-Windows 10 Critical Service Failed BSOD reboot loop. Boot fine with driver signature enforcement disabled.
(mentions installing creators update as a fix, better one I would say)

All System32 drivers are suddenly unsigned in Windows 10
(thread where I posted the workaround and got the Disk Cleanup hint from Eric E Swanson )

Disk Cleanup causing Windows 10 to go into BSOD loop

Windows suddenly won’t boot, “CRITICAL_SERVICE_FAILED”

Windows could not load properly after disk cleanup

Windows 10: Disk Cleanup is causing a Blue Screen

OS is going to blue screen after disk cleanup