Are you running the 32-bit or 64-bit version of Plex Media Server? Look at the top line of Plex Media Server.log. build: windows-x86_64 = 64-bit, build: windows-x86 = 32 bit.
Example: Sep 05, 2024 02:14:27.772 [16248] INFO - Plex Media Server v1.41.0.8911-1bd569c5f - Microsoft PC x64-x64 - build: windows-x86_64 windows - GMT -05:00
Is the Plex Data Folder located on the C:\ drive (default), one of the external drives, or somewhere else?
If you moved it from the default location, did you follow this procedure, including making the registry changes? [HowTo] An extended guide on how to move the Plex data folder on Windows
What is the size of the two database files, com.plexapp.plugins.library.db and com.plexapp.plugins.library.blobs.db?
You can monitor Plex Media Server activity using the Windows PowerShell get-content command. If you’re familiar with Linux, it is similar to tail -f.
gc ".\Plex Media Server.log" -Wait
This can be useful when Plex is performing a database migration. The messages are probably too fast to monitor progress (% complete), but you can at least see if there is any type of activity.