How often does this happen to you?

Just updated our continuous integration and for some reason the BuildAgents, who update independently, just kept failing to update.

Tried every trick in the book, debugged everything.
Kept complaining about being unable to delete files, frigging Windows file system being an idiot as always...
Was about to give up and migrate everything to a fresh system until I realized...

*reboot*
Ah, it works now!

... Why does it always take me so long to realize that's an option!?