Lost data on backup disk


I have a 4TB Seagate drive that I use as a second drive for Time Machine backup plus using it to archive additional large files. Since it is a secondary backup drive (primary backup is Time Capsule) I connect it to my MacBook Pro running OS 10.9.3 about once a week for an update, but otherwise keep it in a safe place. This last time it connected the volume name had changed to its original default and appears empty. I suspect all the files are still there (over 3TB). How can I recover them? Thanks, Ed
Did you disconnect prior to un-mounting?
Try using the repair in Disk Utility. Otherwise, I'd say you need DiskWarrior ASAP.
Yep, when you disconnect an external drive you have to a) dismount it first before disconnecting it, or b) shut down the computer before disconnecting it.

Disk Utility should be able to repair the job. Just remember what ever you do - do not erase or reformat the drive until after you have rescued those saved files.