Encountered this annoying error on Emby the other day. To make long story short, my root disk does not have enough space for a new file. The file in question is the transcoding files that are located in /var/lib/emby/transcoding-temp. Somehow the transcoding folder ate all the free space that my server has. My understanding is, the /var/lib/emby/transcoding-temp directory should clear automatically when the movie was stopped. However, in my case, it didn’t.
The solution is to navigate to /var/lib/emby/transcoding-temp/ and clear it then restart emby-server.service.
cd /var/lib/emby/transcoding-temp rm -rf *.ts systemctl restart emby-server.service
Hope this help. Cheers!