Why does a profile rebuild fix so many performance issues?

[Overkill]

Hello everybody!

I've been working for an MSP for several months and one of the blanket fixes that seems to solve a ton of random issues is forcing a rebuild of a user's profile...this means:

Reboot PC
Log in as domain admin
Rename C:\Users\{Username} to C:\Users\{Username}.YYYYMMDD
Back up HKLM\Software\Microsoft\Windows\CurrentVersion\ProfileList\{SID}
Delete above key
Reboot PC
Log in as user

What I am wondering is why does this work? What information underneath this key could possibly become corrupted? Would it be possible (and reasonable) to identify problems here and simply delete the offending entries/keys instead of the whole SID? I'd love to be able to find the underlying cause instead of just the fix

Thanks,
Overkill

 

[ThrashZone]

Hi
I'm sure there are a lot of reasons
But I would guess most are installed by the user willingly
Weird programs
Terrible security programs....

 

[Overkill]

You'd think that, but these are systems we manage with our own AV and limited user permissions. Some are users I know well enough to say there's nothing other than ms office, web browsing, and network shares being touched by that machine.