Same here and, unfortunately, no positive solution.
Reinstalling the software doesn’t seem to be the solution as you need to have the device recognized for the update to be installed on it (firmware).
I’m using Passport Elite 500G on a laptop running Windows and, since I bought the disk 4 months ago, had blue screens (physical dumps) when disconnecting the device even while using the “Safely remove hardware” utility.
Afterwards, I got this “USB drive not recognized” intermittently but almost all the time now, even after trying on 2 other computers (one Windows desktop and one Mac).
By chance, I was able to “see” the disk again after about 20 attempts this morning, only to get the blue screen 10 seconds later before I could save/retrieve my backup.
Bottom line, I’m stuck like you… Which is pretty frustrating for a backup solution, **bleep**!
