The setting is a reg key and reboot away, has been for years
Lots of stuff today still chokes on long paths.
Sysinternals has had handle.exe since the mid-late 90's to see what's locking a file.
There multiple GUI tools for managing locked files depending on what you need:
File Assassin (uses windows own "delete on reboot" registry key)
FileExile
InUse
Unlocker
These are just the ones I keep on hand. I've used many others.