the above suggestion result in some more files being moved to Library from Inbox, but there are still thousands of files on the monitored drive that are not being picked up for some bizarre reason. As per my previous post...could re-installing MB resolve this, or is there any other method that anyone could suggest first? Thanks.
If you haven't closed MusicBee already, causing the backup of the library file to be replaced, I would make a copy of that backup file, then close MusicBee and move the MBL file to another location. Rename the .bak file to .mbl and then reopen MusicBee. If that library file is pointing to the old location, you might be able to just relink music file paths.