I start this procedure now and then, by using a windows 8.1 installation DVD, pressing Shfit+F10. Todays PC with Windows 8.1 started to check/repair C: after I did this to him and the Accessibility Options do nothing when clicking it at the login screen. Going back to the install DVD, "my" utilman.exe is still there on C:\Windows\System32 I thought this no longer works on later Windows 10 (thanks to smartscreen), but still could be used on Win 8.1 ? The HDD is fine. The system also boots into a guest account without problems. Bad luck or nifty Windows 8.1 Updates ?
don’t know anything about Windows 8.1, but i have the following thing in mind: can you try copying cmd.exe to the osk.exe (onscreen keyboard executable, that also works on Windows 10) and copying the original utilman.exe back. then try clicking the accessibility options and select On-screen keyboard.
After "repairing" C:, the utilman.exe let me start cmd.exe. *yay* Sadly the (local) Admin account is a online microsoft account. So changing the password did not help here. It defenitley wants to go online, says "the pc is offline" when entering the password. The idea was to install a software on another local user, but you need the (online) admin password to install anything. "net localgroup administrators [username] /add" helped here to turn the local user into an local admin.