Cfgupdate.exe -

A corrupted installation can cause Windows to hang for 30–60 seconds while trying to launch cfgupdate.exe during startup.

A well-behaved cfgupdate.exe sleeps most of the time. However, a buggy version might enter an infinite loop trying to contact a dead update server. This can peg your CPU at 20–30% continuously, draining laptop batteries and causing fan noise. cfgupdate.exe