I installed my OS on a new SSD and am using my old HDD as a secondary hard drive. My only problem is that the drive keeps disappearing after a while or if I do anything with it, for example, if I download past a certain size it disappears or if I try and copy something that is too large it will disappear as well pretty much anything involving large amounts of data makes it disappear. The System Reserved partition also disappears when it does. It only comes back after I shut down. It wont come back after just a restart.