|If #6 above is an answer to my #3 above you only supplied partial Disk Management information |
What file system is in use?
Is the disk marked as Basic?
Is there also unallocated space shown there?
If I understand your situation you have a 2TB hard drive, yet Disk Management is reporting about 1TB.
I suggest you go to the drive manufacturers site and download their fitness test to determine what the issue is with the missing space.
What is the full brand and model of the external drive?