PR4100 CPU Pegged by Plex at 99% for Two Days

Please move if I’m in the wrong category.

Yesterday I converted my iTunes music library of about 8,600 songs from *.aif to *.wav and fed it to the Plex app. It dutifully began processing the files but it is still doing so and it’s almost noon the following day. There are several Plex processes running but only one is using any resources and that one is at 99% CPU but only about 7% memory (I have 16 GB). The PR4100 is 40 TB in RAID 5.

It appears that Plex has recognized all of the albums so I assume it is still doing something with the individual songs although I can no longer see the icons for a given album showing activity.

Is this normal behavior? Do I need to reboot to clear all of the inactivity Plex processes?