Synology running Plex will not even recognize .mkv files in my TV directory

[tom80H]

The Syno server should have no problems recognizing mkv files. From your description it sounds like there might be a permission issue.

If you’re on DSM 6, make sure the Syno account Plex has access to those files (and don’t store your media in the Plex share).

Synology FAQ - Questions, Answers, and a few How-To's

FAQ 19: Setting permissions to allow Plex access to media files Before beginning, it’s important to remember one key point; Plex doesn’t have any special privileges on Synology except for being able to access the Video Transcoding acceleration hardware. It cannot read any of your files unless you expressly grant permission. This is a fundamental principle of Linux (which Synology uses for DSM) Because of how Synology grants permission, access to files is broken into two different …