I have My Passport Essential ES 1TB with same drive letter disappearing issue. It fogets it’s drive letter if I kept disconnected for few hours. (It wasn’t an issue for me as I keep this drive connected - It sleeps 99% of the time) Today I did something different. While the drive is not showing the drive letter, I right click and choose, “make the partition active” while I was in disk manager.
Now it shows as "Healthy (Active Primary Partition). Immediate disconnection - reconnection will not show this problem. I need to disconnect and set aside for over night t be sure if this is working or not.
I’ll keep my fingers crossed!
If the issue is fixed tomorrow, it will be a good news for you and me.
(Or we’ll have to wait until new FW fix this issue)
Mabikay - SLK