I have a question about the file organization of the Plex server software. I’m running the Plex server on a Windows PC with 8 HDDs, but not in RAID; they’re all individual drives. If I replace one or two HDDs with larger models and also move the files on the HDDs, e.g., files from HDD 1 to 4, etc., will Plex regenerate the video preview for each file that’s no longer on it’s original drive, or does Plex create a kind of hash value for the files when it’s first scanned, and use that to recognize when a file is on a different drive after the library has been rescanned?
Plex will need to rescan the files it will update the meta info to where your films them resides
as far as I know it will need to regenerate the video preview
Unsure why anyone bothers with this feature as it takes forever and takes a very lot of space just so on a app you can see the pictures whilst fast forwarding or what ever I normally just use the time and go to the rough spot if ever I have to go back to a bit or just the chapter images
Think different™ 
There is no need to reorganize your files if you want to migrate one of your hard drives to a larger model.
Simply copy all the folders and files as they are (i.e. without reordering or renaming them) from the old to the new HDD.
After that, do this:
- if you have automatic or periodic library scan active in Plex, disable it
- stop Plex server using its task tray icon
- swap the drive letters of old and new HDD in Windows storage management
- remove the old drive
- verify that the new drive still has the intended drive letter assigned (only necessary if you moved it from external to internal during step 3)
- start Plex server.
Plex won’t even notice that something has changed. So it won’t need to recreate any thumbnails or other analyses.
Other general tips:
- never point Plex to the “naked” drive letter. Always create one or several folders and add these to your Plex library(s)
- name your hard drives in Windows
- never let totally empty or no-longer-existing folders remain added to a Plex library
I would like to copy a larger number of files to other hard drives for better organization. Originally, I had TV series on specific drives, as well as 2K and 4K movies. Over time, as I upgraded movies from 2K to 4K, more and more files were deleted from one drive, freeing up space, and that’s when the chaos began. To avoid wasting space, I started saving new files there, and now it’s gotten so bad that some TV series no longer have all their seasons on the same drive, and some 2K, 4K, and TV series files are even scattered across the same drive, which isn’t what I originally intended. It’s become completely disorganized.
I wanted to completely reorganize my files when I’m going to replace two HDDs with larger ones, but if that requires regenerating the video thumbnails, it’s a complete disaster because, as piraterider1 pointed out, it takes forever. The worst part is that Plex doesn’t even use all the CPU cores and/or the GPU for this; it only uses one CPU core. I simply can’t understand why Plex still doesn’t use all available cores for this in 2026.
I also don’t understand why the developers didn’t program Plex’s file management, as I wrote, to generate a hash value the first time a file is read. This would make file handling much more flexible. I’m certainly not the only one who has distributed their library across separate HDDs.
Now I obviously have a BIG problem if the previews are regenerated when files are reorganized…
PS: Thank you both for your answers
not sure if this applies to you but since this is about moving files around there is another issue, if you make optimized versions and transfer files to a new location plex will automatically make new versions from the old versions so you end up with double the versions. it will use the optimized versions you have and generate new ones inside the plex versions folder. back in the day it would recognize you had plex versions and accept them as such but not anymore
