Get full full capacity of external 2 tera Seagate that now is reaing only 110 gig

This has happened to me before, also. What I had done was copy a disc IMAGE from the old, smaller drive to the larger drive - and the larger one turned into the same size! You did not mention your operating system (Windows, Mac, etc) but my solution was in Windows to go to Disk Management function and view the unallocated space left. Sure enough, there was "unclaimed/unused" space for the entire difference in size. Following the instructions of the Disk Management tool, I just added the remaining space to what was C: drive. I could have just as easily created a different drive space with the leftover, it's up to you - but I find it preferable to have my space in one chunk.

Note: This is a very sensitive area of Windows when you're dealing with file systems. A raw beginner might want to have an experienced friend help them through it, but if you follow instructions EXACTLY even a first-timer should be able to do it. If this solution does not work, let us know. Best wishes - Mark

https://www.lifewire.com/how-to-open-disk-management-2626080

How To Open Disk Management