How to get file permissions back after reinstalling Windows?

Question

NTFS

I reinstalled Windows 7 x64 Ultimate and lost control of my files on my NTFS system drive as a result. You can access the files, but the UAC dialog pops up all the time, which makes working with "own" files only theoretically possible. The files are now owned by some user with a GUID instead of a name.
Question : a) how to find all such files and b) regain ownership over them in this situation?
It would be even better to do so that such a problem, in principle, could not arise. Rejecting NTFS/UAC is not an option.

Answer 1

There was a good program from the small soft ones called subinacl, which made it possible to massively replace one SID in all files recursively with another. Moreover, you don’t even need to be the owner for this, the main thing is to run it under the administrator.