Just a heads up in case anyone else has this problem ...
Since upgrading to PMS 1.0.0, I get the following error when trying to shuffle TV shows from the main TV show screen:
Unable to play media: Please check that this file exists
If I go to All Episodes and then shuffle, everything is fine.
The computer is a 2012 Mac Mini OS X 10.9.5, all files are stored locally on external hard drives, and I verified that PMS had the correct file paths for several files in the TV shows I tried shuffling. I updated the PMS libraries, emptied trashes, optimized the database, and cleaned bundles. No luck. Thinking perhaps there was a permissions problem, I changed all permissions in the hard drives to 777 and removed all extended attributes (the @ permission), but that didn't help either.
In the end, I rolled back to PMS 0.9.16 (link below if anyone needs it), and now the problem is fixed. As a bonus, episodes now are correctly marked as watched after I watch them.