Unable to play audio file

After 8 years of successful functioning suddenly about 50% of my library won’t play anymore. "Unable an audio file for playback’ is said. Also some tracks open the wrong track. Some are fine. All are stored on a NAS. The NAS is functioning well and the files corresponding with the unplayable tracks can be opened and played on the NAS directly, so no file corruption.

I opened the Audirvana Library folder and removed the files. I started Audirvana again which promted me that my library had to be migrated. I said OK and in one second the library was rebuild. To me this didnt look as re-indexing. More importantly, the exact same issue occured again.

Nothing has changed regarding HW or SW in my system chain. Only thing I did do is setting up a backup of my NAS (via HyperBackup app on the NAS) to a cloud-environment. Can’t imagine this caused the error, but computers never do something on their own so it might be worth mentioning.

Can someone help on this?

That could be the cause, as backup operations “privatize” the files while reading them.
Try to disable the backup to verify this.
Backup is a must, but it is better to run it when nothing else is accessing the resources.
I think it should be better to schedule backup late night, when nothing else is running

Thanks for explaining. But I do not think the backup causes this as it doesnt run now. Only at night. And the music folder is excluded from the backup. But I will test for sure!

Doublechecked: backup isnt running now. Also, some tracks start a different track (from other artists or albums). So it seems to me the index is on steroids.

Try to execute the three dB maintenance tasks: check, rebuild and defragment