This data drive disappeared from the system two days ago. I've had problems with drives in that bay when rebooting into Ubuntu from Windows and so I put it in a different bay and it seemed to be working well after reboot. Today when I rebooted into Ubuntu from Windows, I saw Deluge showing errors and unable to recheck files cleanly. Running fsck -a gave

fsck from util-linux-ng 2.17.2
/dev/sdc1: One or more block group descriptor checksums are invalid. FIXED.
/dev/sdc1: Group descriptor 0 checksum is invalid.

/dev/sdc1: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.
(i.e., without -a or -p options)

But running fsck manually, I get

One or more block group descriptor checksums are invalid. Fix<y>? Y

THen lots of:


Group descriptor 888 checksum is invalid. FIXED.
Group descriptor 889 checksum is invalid. FIXED.
Group descriptor 890 checksum is invalid. FIXED.
/dev/sdc1 contains a file system with errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Free blocks count wrong for group #335 (32768, counted=5759).
Fix<y>?