How to check which files to close to avoid restart?

Hello,

I have bought a new PC and having installed windows, various other things including WSL2 I wanted to do a disk to disk copy.

Unlike my previous computer, where I could keep working while the copy went on, this copy gave me a choice of restarting or closing "open files".... it would have been helpful to know which !!

I am running hard disk manager 15. Is there any way to find out which files specifically need to be closed to avoid a restart? It's very inconvenient. Is there a log file I could inspect to give me a clue?

Thanks

Brian Williams