My NAs says it's full but, before I start deleting files, there's a 400 GB discrepancy which I'd like to investigate. (Hopefully, I can reclaim some of that 400 GB instead of deleting files.)
The web UI shows:
Volume Name   Volume_1
Volume Type   RAID 1
Sync Time Remaining   
Completed
Total Hard Drive Capacity   2748.19 GB
Used Space   2748.19 GB
Unused Space   0 MB
But Windows (specifically, TreeSizeFree scanning the Volume_1 share) shows only 2.33 GB is used.
I have SSH access to the NAS. How can I find the missing 400 GB?