3 TB internal drive disappears intermittently

oldster

Honorable
Nov 16, 2013
6
0
10,510
Using windows 7 ultimate. My 3 TB Seagate internal drive disappears intermittently. I have it partitioned into 3 1 TB logical drives. It's ok for hours (sometime days) then suddenly goes away.
A reboot will bring it back. Anyone have any ideas what may be wrong?