In rare cases, users running Plex Media Server on Windows computers may encounter seemingly random transcoder-related issues. These can manifest as errors during playback of library media requiring transcoding as well as issues watching live TV or with DVR recordings. One common cause for such errors can be due to the “Web Protection” feature of MalwareBytes Premium.

Users encountering the underlying issue may see one of the following when trying to play content:

• Conversion failed. The transcoder exited due to an error. appear in an app when trying playback
• Recording failed. Please check your tuner or antenna. appear in an app when trying playback
• Hardware transcoding gets aborted and the server falls back to software transcoding

Investigate the Server Logs

To verify that the “Web Protection” in MalwareBytes is, indeed, the issue here, you’ll want to look at your Plex Media Server logs. In all cases, the Plex Media Server.log file will have the following error logged (which you can search for, after you open the log file):

ERROR - [Transcoder] av_interleaved_write_frame(): Unknown error

For instance, the following are log snippets for examples of two different manifestations of the problem:

ERROR - [Transcoder] [stream_segment,ssegment @ xxxxxxx] Failed to open segment list 'http://127.0.0.1:32400/video/:/transcode/session/xxxxxxxxxxxxxxxxxxxxxxxx/xxxxxxxxxxx/seglist
ERROR - [Transcoder] av_interleaved_write_frame(): Unknown error
ERROR - [Transcoder] Error writing trailer of media-%05d.ts: Invalid argument

ERROR - [Transcoder] [dash @ 028ef3c0] Unable to open http://127.0.0.1:32400/video/:/transcode/session/xxxxxxxxxxxxxxxxx/xxxxxxxxxxxxxxxxx/manifest for writing
ERROR - [Transcoder] av_interleaved_write_frame(): Unknown error

The errors would precede the following DEBUG log entry:

DEBUG - Jobs: 'C:\Program Files (x86)\Plex\Plex Media Server\Plex Transcoder.exe' exit code for process xxxxx is 1 (failure)

If you see logs similar to this and you’re running MalwareBytes Premium on the Windows computer, then you’re almost certainly encountering the same issue.

Fix the Issue

To fix things, the majority of users simply need to configure MalwareBytes Premium to not interfere with the various Plex Media Server executables. You do this by setting up an exclusion for each executable.

• Refer to the MalwareBytes documentation on exclusions for information on how to create/configure an exclusion
• When creating the exclusion, choose the Exclude an Application that Connects to the Internet option
• We recommend adding a separate exclusion for each server executable (all found in the C:\Program Files (x86)\Plex\Plex Media Server directory, by default):
  • CrashUploader.exe
  • Plex Commercial Skipper.exe
  • Plex DLNA Server.exe
  • Plex Media Scanner.exe
  • Plex Media Server.exe
  • Plex Transcoder.exe
  • Plex Tuner Service.exe
  • Plex Update Service Launcher.exe
  • Plex Update Service.exe
  • PlexRelay.exe
  • PlexScriptHost.exe

Note: If you continue to see the same errors even after adding an exclusion for each of the executables above, we recommend providing in this MalwareBytes forum topic, to help MalwareBytes investigate.

Related Page: Exclude detections in Malwarebytes on Windows devices

(Thanks to Plex user XenonMB for assistance in investigating the cause and solution for this issue. Further information is available in this MalwareBytes forum topic.)