This can sometimes be caused by an improper shutdown or Windows updates that didn’t install properly.
Click Start and type in regedit. Choose “Run as administrator” either by clicking it on the right hand side or by simple right-clicking the icon and choosing it.
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList
Each one of these keys represents a Windows profile. Find yours by clicking through and paying attention to the ProfileImagePath value. Look for your username.
When one becomes corrupted, Windows adds .bak to the corrupted registry key and creates a duplicate registry key that points to C:\Users\Temp.
First delete the temporary key (without .bak) and then rename the original one by removing .bak at the end.
Reboot the computer and it should be back to normal when you log back in. (I’ve attempted just signing out and signing back in but the problem persisted. I believe the reboot is necessary.)