I was scratching my head for more than a month trying to find a solution for this problem, and now managed to find a work around solution i am somewhat satisfied with.
My issue happened shortly after the windows 10 anniversary update, i had short 4 digit pin configured for quick login and after the update it disappeared only allowing me to enter my full-form MS account password, it seems the MS changed some security configuration for pin codes and broke the feature for many users, problem is, you cant disable it, delete it or rest it, I could have just rolled back to a checkpoint and tried my luck again but I was determined to solve the issue my self.
I found a solution to delete Ngc folder contents under this path C:\Windows\ServiceProfiles\LocalService\AppData\Local\Microsoft\NGC
reference - (Fix: PIN Sign in is Not Available in Windows 10)
Sounded a bit risky, but after a battle with file/folder ownership i thought, the hell with it, Ctrl-a shift-del.
Not only that it didn't fix the problem, now after sleep the login prompt doesn't appear at all.
long story short, here are my findings, work around and a solution:
1- If you are unable to login even after a hard reboot then try to rdp (remote desktop) the machine, it will normally work if the machine is connected to wifi or lan, you can login through RDP and reboot in safemode.
2- If your OS is as useless as mine win10 (home edition) which doesn't even allow RDP then install rdpwrap - guide (Enable Remote Desktop on Windows-10 Home, how to?)
3- In some cases login prompt will appear only on hard reboot, in this case restart login and enable RDP, use mobile version of rdp to save your files and restart if your machine fails to login after sleep or hibernation.
-The solution was to actually delete the NGC folder it self, as once the folder ownership is changed the system isn't able to access it, so just delete the entire Ngc folder.
doing above didnt restore my pin code functionality but i was able to configure picture password and toggle between actual long form password if needed.
hope this helps, i was able to replicate the issue on two other windows 10 boxes part of my troubleshooting, solution above worked on all.
good luck
I had taken ownership of my entire hard drive. After that I ran into a series of issues. This was the last one I had to deal with. I ended up adding the SYSTEM and LOCAL SERVICE accounts to that folder and gave it modify rights. That ended up fixing the issue without deleting the folder.
sorry wrong thread!
I had done the same thing, and I am thankful to have stumbled upon this thread. I can confirm that the method of adding SYSTEM and LOCAL SERVICE back to that specific folder (C:\Windows\ServiceProfiles\LocalService\AppData\Local\Microsoft\NGC) has resolved the issue. I readded the permissions and rebooted and I now have my login screen when returning from a locked state.
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