Did you replace uxtheme.dll for user themes programs like brico pack?
If you did, it is most like the acl (access control list) of the patched uxtheme.dll that is causing the problem.
open command prompt:
cd c:\windows\system32
cacls explorer.exe
Check if "BUILTIN\Users:R" is listed.
If not, then grant Read-only access permission to all users:
cacls explorer.exe /e /p "BUILTIN\Users":r
This should fix the problem. If not do the same to explorer.exe, and other dlls that is loaded during log in.
Good luck
