Running

FSUtil 8Dot3Name Scan /v /s C:

gives you a list of potential 8.3 paths in the registry that are referring to your file system, but is there any tool that can actually convert those paths to long paths in the registry?

I do understand this could break some programs, but I have backups so I'd be willing to give it a try.

(I tried to make a tool like this myself, but it's harder than it looks, because of false positives and all the varieties of ways the path could be embedded.)