I have some libraries (music, archived tv, etc) that rarely have new content added to them.
The only boxes ticked on the Library settings page are “Update my library automatically” and “Run a partial scan when changes are detected”
And yet I keep finding these libraries in the middle of an update when no changes have been made. (Yes, I am sure no changes have been made.)
Is it possible to straight-up exclude individual libraries from updating without a manual click of “Scan Library Files”?
@trumpy81 said:
You cannot include/exclude specific folders from updating unless you use .plexignore.See this article: https://support.plex.tv/hc/en-us/articles/201375253-Excluding-New-Content-with-plexignore
Thank you, @trumpy81
Dang. I sure wish this were possible without .plexignore. 
I’d rather not turn off automatic updating or partial scans altogether, as it works quite well on the one (and only one) library I need it on. Except of course when the scanner is pointlessly scanning the other libraries. Because that takes forever meanwhile the one and only library with any updates has to wait.
There is no cross-contamination of libraries or their included directories. Media folders listed in one library are listed in no other libraries.
Download programs do not download to the media folders. Sickrage copies files into one media folder, but that media folder is listed only in the library that I do want updating automatically.
Video preview thumbnails have been disabled on all libraries since the moment of library creation.
Scheduled tasks runs from 02:00 to 05:00, but I’ve noticed libraries updating at intervals throughout the day. Even if I don’t cancel but just let the scanner do its thing, it’ll kick itself off again for reasons I can’t determine.
Correct me if I’m wrong, but it’s my understanding that if you exclude something with .plexignore (something that’s already in your Plex library), Plex will remove those items from the Plex library, not just stop updating it.
@trumpy81 said:
@watchvera Given your response, it only leaves other programs triggering an update somehow. […]
Try having Sickrage download to a non-Plex watched folder and use FileBot to rename and do the transfer if that is at all possible
Right on. I’ve got Deluge downloading to a directory that Plex isn’t aware of. The SickRage postprocessor renames and copies from that directory into one that is watched by Plex. Said Plex-watched directory is the one-and-only media directory for the library (Recent Episodes) which I do want to update automatically. This all works flawlessly.
But other libraries, such as movies and tv-archive, are also updating automatically. The media directories behind these libraries are unknown and untouched by SickRage. And Deluge, for that matter. In fact the only program aware of them at all is Plex. I add content to these directories strictly manually, and infrequently.
An option such as “Include in automatic updates” in a library’s Advanced settings like the one for “Include in dashboard” would be reallyvery rad, I think.
Thanks, btw, for the insight folks! 
As a sorta follow-up to this, I went ahead with the advice from @trumpy81 to turn off “Run a partial scan when changes are detected” even though I still wanted that happening on one library. Choose yer battles, right? ¯_(ツ)_/¯
So now all of the checkboxes on the settings page at Server > Library > Show Advanced aside from “Run scanner tasks at a lower priority” are unchecked. Preview thumbnails are set to never. (Both here and on each individual library.) Chapter thumbnails are set to never. No source directories are shared between libraries.
Still, libraries are updating of their own volition. Outside of the Scheduled Tasks windows. When no items have been added to the source directories. Curiously, music libraries are not exhibiting this behavior. So I suppose the unchecked “Include music libraries in automatic updates” is being heeded.
I’ve not ruled out the possibility that @trumpy81 is on to something re: the filesystem being accessed by another program. It probably is. But even so, should automatic scans be happening at all, ever, with the settings configured as they are?
Dang you trumpy81, I was going to post about the USB but you’re faster then me 
@watchvera after unchecking all those settings have you stopped/restarted the Plex server? I don’t think you need to but it’s worth a shot if you haven’t restarted Plex.
What you could do to help diagnose a few things is to stop the automation of the scripts you use to add to the Plex directories. Check the modified times to make sure nothing is updating them without your knowledge. See if Plex is still rescanning these libs.
Now manually run the scripts that move the files into Plex and note what happens.
Also of course worth checking is to see if you have ever used any feature such as “update plex libraries” in any 3rd party programs. Many of the 3rd party programs have such a features and Plex could just be following directions given to it from such program.
Don’t know if any of this is a help or not but I thought I’d throw those ideas out,
Carlo
Thank you @trumpy81 and @cayars for the USB and 3rd-party/script suggestions. One of the offending libraries is indeed on a USB drive, so I’ll try moving that content and reassessing. Also, although I have cut CouchPotato out of the loop regarding these directories, it is still installed. I don’t believe I ever set it to “update Plex libraries” but I must admit I had forgotten of this setting entirely.
Both of these suggestions are worth looking into, and I’ll give them a go when I get back to my server. As always I appreciate the insights. You folks are top-notch!
Keep us updated on what you find. These types of things can be very frustrating but there is usually some reason why something like this would happen.
It took a bit of time to transfer library files, and some culling of less-important media, but I’ve got the USB drives removed as source directories. Since doing this, I haven’t noticed any unwanted library updates running! It’s a bummer to not use those drives, but hey, at least the annoyance of unwanted updates is gone! Eventually I’ll find time to look into if updating the USB drivers is a possible option, so maybe I can use the external drives again.
