This is a very recent occurrence for me. I've been using Plex for a LOOOONG time and I have never had an issue like this. It's basically become unusable for me. Every video I try to load gives me the "Transcoder failed to start, Exit code 1" error message.
I've been searching all over the place for an answer and haven't come up with anything that works. I've tried rolling back to previous versions with no results. I've seen posts in the linux and Windows forums about this but so far nothing in mac. I'm at a stand still. Anyone have any suggestions?