Hello TeknoJunky,
First of all, thank you very much for your answer.
I have followed your advice and had a look into the PMS log.
I saw a lot of errors (and some about missing libraries…)
A pretty big mess in there. So I resigned myself to reinstalling completely the PMS (and to deleting the Plex directory and the plex user).
After this reinstall I had a look at the Synology Disk Station Manager settings and… I found out what had happened in the first place.
The answer is in this community announcement by ChuckPA
Shame on me… Moved by a cleaning compulsion (not an OCD symptom but close) I had this wonderful idea of deleting the Synology user group called “video” (this group is created during the PMS install). As ChuckPA says in his community announcement, this user group is mandatory (now I know) for providing to the plex user the access (special privileges) to the hardware acceleration ressource of the NAS.
I am a bit sad that now I have to rebuild all my libraries, but I am glad the hardware transcoding is working again. Moreover I am not sure it would have been possible to (re)create this special “video” user group manually…
Regards,
JerHome.
