PMS refresh all metadata when I add new files. How to only scan them

[DrMalex]

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Hello everyone.
I have an annoying issue with my PMS on Synology NAS (DS1520+). I had an old NAS (DS1515+) that died and change it with the actual one.
Before the change, everything was working fine. PMS use to scan my new files and update their metadata without touching other files in the library.
Now, if I add or modify a file, it start to refresh all the metadata of the files in the same library (or folder), messing up all the settings I previously did.
I put the flag on the options “automatically scan library” and “only folder” because without these, if I had a new file, system seems not to scan it.
For what I remember I didn’t have these two options flagged in the old NAS settings.
My question is: how can I set PMS to scan only the new file I add? Without touching the metadata of the other files in the library/folder?

hope I was clear enough in the description of the issue and someone can help me.

best regards

[DrMalex]

thanks for the reply trumpy81.
I am already doing this naming procedure (still a big part of my files doesn’t have it, but now when I add a new file I always put the right name).
The fact I don’t understand is why plex is scanning the entire library, since a month ago (when I had my old NAS) this never happened. Every time I added a file, the system looked for the info of the new file but without scanning the library/folder. This scanning is also requesting a lot of time everytimes. If I had 1 file, then it starts the scan procedure and that takes 15-20 minutes.
If I doesn’t flag the “auto scan” and “only folder”, should plex recognize the new files? (again, I didn’t remember to have these options flagged in my previous settings with the old NAS and the system worked perfectly).

thanks again