W7Px64 My \Windows\System32\DriverStore\FileRepository is 8.5GB. Why is it so big? Can I safely pare it down if so how?
As the name implies it keeps a copy of every driver ever installed. It starts off at less than 1gig containing a variety of misc/standard drivers- basically the default pool. If you've installed several large packages, for instance gpu driver packages tend to be rather large for nvidia and amd, they'll add up rather quickly across versions. You *could* manually take ownership and remove the old ones but the folder names may end up being tricky as they tend to be strings with no clues, for instance my gpu driver is 'c7188451.inf_amd64_neutral_7ccf1804f7fdf2d9' Sorting by size may help you find the biggest culprits and allow you to identify what they are by checking the file properties of a few inside each folder.
I do nothing in particular. I clean the disk regularly with Windows Disk Cleaner and CCleaner, don´t know if this affects this folder in any way.
Well I went through them a couple at a time. Used Iobit Unlocker 1st time, I am impressed. I rebooted a couple times between each volley of uninstalls. Moved the files 1st So if I borked I could fix through a LiveCD. Recovered over 6GB. I'm happy with that.