I'm using Windows 8.1 Update 1, and this morning I tried to install StartIsBack, I launched the setup and clicked Install, then it restarted the explorer as I expected but explorer.exe entered into a restart loop, I mean it starts and 1 seconds after it stops and then restarts, indefinitely, without any error message. I tried to do a SFC /ScanNow, nothing changed. The problem isn't present in Safe Mode. Thanks
EDIT: I managed to start cmd.exe, and apparently explorer starts without any problem if I run it as admin, so as a temporary solution, I went in the file properties and checked "Run this program as admin".
EDIT 2: After around 30min of use, I've noticed that explorer.exe stops after 5/10 min.