Because I hate it when other people leave their topics just dangle, even after they found a solution, allow me to update this briefly – especially because the “solution” here was ridiculously obscure:
In a nutshell, all of my recent problems since the migration to a Mac server came down to one evidently corrupted folder on my NAS.
I stumbled upon this by accident, when copying all of my data to an external drive in order to test moving all media files to a new location to fix the problem described here. Every time I tried to access this folder (one season of one show) in Finder, Finder would crash. Like, completely. Spinning wheel of death, unable to restart either Finder or the Mac, needed to hard reboot. Every time (beforehand) when I selected multiple (or all) folders to copy with this folder included, the entire network share would eject. I couldn’t even delete the folder, as that also resulted in Finder crashing.
So, once I was sure (through painstaking – and painful – manual trial and error) that no other folders on my NAS were having the same effect, I simply copied all data except that one folder to the external drive, then completely wiped and factory reset the NAS and the drives in it. Afterwards, I copied all the data back, minus that one folder.
Lo and behold: Everything works now! Not only does Plex now find and add all shows again (before it must simply have quit whenever it hit the corrupted folder part of the way through the library scan), I’ve also had zero disconnections of the network share following library scans.
I literally have no idea whatsoever how one corrupted folder (or even one corrupted file in one folder), especially one stored on a NAS (i.e. not even on the server itself), can cause issues on this scale. But, empirically, it somehow did.
I’ve now set up a new data scrubbing schedule on my NAS and hope this will prevent anything like this recurring in the future. And while this is probably a one-in-a-million edge case, I still wanted to leave this here for anyone experiencing similar symptoms. Make sure you check the integrity of your files!
