Since Saturday last week (7 Apr 2018), I am experiencing strange problems with a lot Windows 7 installations.
The problem is that user profiles get replaced with temporary profiles. In the registry, under key HKLM\Software\Microsoft\Windows NT\CurrentVersion\ProfileList, the profiles get renamed to .bak and a new profile with directory C:\Windows\Temp gets created.
Most of the time, the profile MSSQL$... gets damaged, which renders SQL Server 2012 unuseable. But I also noticed this issue on several non-SQL-Server profiles, including the user profile on my private computer.
After renaming the ".bak" key back to its original name, the profile actually works fine again.
Since last Saturday, 8 independent customers* had this problem, and also my own profile got corrupted. The weird thing is that I could not see any recently installed Windows Updates (except MSSE updates) which could have caused the issue. I also didn't find any Malware that could cause the issue.
I didn't find any blog or forum post which reports that people have this problem recently; I cannot find any news article which mentions this problem. My question is, if you have any experiences with this issue. I am becoming very concerned and am wondering if there is a new Windows Update or maybe a new virus which breaks profiles, but I cannot see any news on this subject.
(* each customer has their own private Windows environment; they do not share same configurations, software or system properties)