3TB Green Disk now only has total apacity of some 800GB

Hi. I bought a Green 3TB internal drive in March 2015. I put in in an enclosure and use it as a Time Machine backup for my iMac. Everything worked fine until one month ago, when the disk didn’t mount in Finder.
After some experimenting with different disks and enclosures i have lying around, i was sure that the green drive was the problem. Although it didn’t mount in Finder, it was visible in Disk Utility as a 800GB drive. Hitting VERIFY showed following message: check failed because no slices were found. REPAIR wasn’t possible for the same reason.
I decided to reformat (using Disk Utility). Now, I have a disk that mounts in Finder, but only has a total capacity of 800 GB.
Is there something i can do, or is this just a defective Hard Drive?
Thanks for helping me out, I don’t feel comfortable without my Backup.

I apologize. In a moment of greater lucidity (or less stupidity :smile: ), i detected the problem.
The second enclosure I used, probably didn’t ‘accept’ 3TB disks, so the disk was formatted as a 800 GB disk. When I put it back in the first enclosure there wasn’t a problem, and i could reformat to a 3TB disk. My mistake.

Hi, glad to see that you were able to resolve the issue.