"Which LE are you running?"
LE 11 nightly from 30/07/22
"What errors did you get? What was the corruption?"
The Kodi simply told me my sources were empty and would I like to open the files section. When I tried to reset the sources I could navigate to the disk but not down to the folders.
Windows when I plugged in told me there was corruption and offered to scan and fix. I opted to run CHKDSK and was shown the most index errors I've ever encountered. Ran CHKDSK /f and ended up with an apparently blank disk.
I'm currently carrying out a full format - 6TB will take a while.
I also had another thought - LE & Kodi are on a separate SSD, the Seagate is used purely for media split into folders - Films, Music videos and Records would Kodi (or LibreElec) even write to the Seagate? If not then there must be another cause.