hendrik on 17 Oct, 2019 11:38 AM
That’s quite the sizable library!
Frankly, I have no idea how long 18,000 changes usually take!
But, if you are using an iTunes-based library, all changes are communicated to iTunes via AppleScript and then iTunes is the program that actually applies the changes to your files. In your case, each change involves a network drive operation and that is most likely the bottleneck.
Storing music on a NAS is a great idea, when you only listen to music, but never manipulate the files.