Updating my collection - problems

I maintain a master music collection on my main computer, and play from a separate NAS, which I keep synchronised to the master collection. So every time I buy some more music, I first download or rip or digitise it to master collection, then synchronise that collection to the ‘playing’ collection on the NAS.

What I notice is that the software, which automatically picks up modified files as well as new files, always updates many more files than the new ones, and automatically updates some files every time.

Is this as a result of Roon modifying the files once they’re on the playing NAS? (so that the software picks them up as having been modified?)

Roon doesn’t modify any media files. What software do you used to syncronise? You may be better served by pointing Roon to the master files and backing those up to the alternative location.

Roon plays from the “Playing” NAS, your sync software syncs from the “Master” to “Playing”. Why/how do you think Roon is changing the “Master”? I suspect something else is responsible. In any case, as @Martin_Webster says, Roon doesn’t modify any files, it maintains its own database of file location.