When running Plex Media Server on a Windows computer (and particularly if you’ve upgraded from a much older version of the server), it’s possible you might encounter transcoder-related issues. This might manifest in multiple ways, but some common symptoms include:

• Content can Direct Play, but fails when any type of transcoding is needed
• Media analysis fails and you don’t see media format information on item details/preplay screens

Verifying the Issue

You can verify whether this particular error is causing your issue by examining your Plex Media Server logs. Affected users will have a log line similar to one of the following:

ERROR - Unexpected error configuring transcoder: boost::filesystem::unique_path: Key not valid for use in specified state

ERROR - Unexpected error configuring transcoder: boost::filesystem::unique_path: Keyset as registered is invalid

Unexpected error configuring transcoder: boost::filesystem::unique_path: Key not valid for use in specified state

Unexpected error configuring transcoder: boost::filesystem::unique_path: Keyset as registered is invalid

After reproducing the issue, look inside your Plex Media Server.log or Plex Media Scanner Analysis.log files and then search for “Key not valid for use in specified state“ and “Keyset as registered is invalid“. If you see a log line similar to above with the text, then you’re affected by this issue.

If you’re not sure what to look for or where, post details in our support forums and be sure to attach your full set of Plex Media Server logs.

Related Page: Plex Media Server Logs
Related Page: Plex Forums – Plex Media Server > Computers

Resolving the Issue

The following steps will resolve the issue for the vast majority users.

1. Stop/exit your Plex Media Server so it isn’t running
2. In Windows Explorer, rename or move the following directory: %APPDATA%\Microsoft\Crypto\RSA
3. Reboot the Windows computer
4. Start Plex Media Server

That should cause the cryptographic cache information to be re-built automatically.