Plex Media doesn't detect automaticaly new media

[ChuckPa]

It is likely you have more directories now than the default Linux table allows.
This is pretty easy to resolve.

Using File Manager,

1. Go to a media share
2. Right-click it → Properties
3. Let it count the number of files and folders. We are interested in the number of folders.
4. When you are all done counting all the folders in use, if that number is greater than 8192, then you have the answer.

Syno FAQ #16 will help you.

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

FAQ 16: Increase the number of folders Plex can monitor Applicable to all supported versions of DSM. When the Linux ‘inotify’ table fills up, this will cause when Plex to stop automatically detecting new media you add to the server. It will also manifest when there are transcoder problems with Dolby audio codecs. Linux has a default table size which is static. We can increase this at will. On some versions it’s 8192. On newer kernels, the default is 65536 folders. This is easy to in…