Malware often uses wuauclt.exe as a disguise. Legitimate file is in System32 . Check:

net stop wuauserv net stop bits net stop cryptsvc ren C:\Windows\SoftwareDistribution SoftwareDistribution.old net start wuauserv wuauclt /detectnow

Wuauclt.exe relies on dozens of DLL files (Dynamic Link Libraries). If even one core DLL is corrupted—like wuapi.dll or wups2.dll —the client will crash on launch. This is often the result of a failing hard drive, a bad RAM stick, or an interrupted OS update.