Not enough free space (3108864) to import: /share/CACHEDEV1_DATA/Download/_AutoDownloads/_TVDone/The.Big.Bang.Theory.S12E05.The.Planetarium.Collision.720p.AMZN.WEB-DL.DDP5.1.H.264-NTb/35gYWBkxyw3YwrmDtsJxkxxcQR24xDKbWmXwd2k.mkv (587016340)
The file in question is 559 MB
But I do have plenty of space. Sonarr itself detects that I have:
/share/CACHEDEV1_DATA 1018.4 GB (free) 3.5 TB (total)
Version 2.0.0.5252
Mono Version 4.6.2
QNAP TS-451A
Current firmware version: 4.3.5.0728
Sonarr is unable to properly get the free space for that particular location for some reason (the logs might indicate why) and is using the space for / likely. You can disable the free space check in settings.
Found the problem. It was a file system problem, not related to sonarr at all.
On the latest QNAP update, they made a file system change that screw some thins up.
In case this can help someone else, this was the thing:
My “TV” directory is actually called something else, and I have an alias (i don’t know the linux terminology- a shortcut) called "TV ". The system created an actual dir called “TV” which overwrote the alias. Sonarr was trying to copy files there.
The solution was to erase the new “TV” directory and create the alias again.