I've long had a AcomData 60GB HDD with firewire and USB2 interfaces. I had out-grown the 60GB, so upgraded the drive to a Hitachi 250GB drive. The upgrade went fine (using the firewire connection) and I transferred all my data over to the new drive.
The problem, however, is that I discovered, when trying to use the USB connection on a computer that lacks a firewire connect, that Windows can no longer see the HDD: it shows up in Windows as an unformatted drive and Windows can't read the size. Double clicking causes Windows to want to format it.
I've played around with the master-slave settings on the new drive; as far as I can see, only Master works at all (that is through the firewire connection but not the USB). Nothing else works.
I've been tempted to format the drive, but I would hate to loose 200 GB of data, which I can't fit on my tiny internal laptop drive...
Any suggestions? I'd love to be able to use this as a truly portable drive and this has been driving my insane.
What Windows version was on the machine that could not read your upgraded drive? Win XP original version could not deal with HDD's over 137 GB. It has to have at least Service Pack 1, and much better to go to SP2. That allows Windows to use larger hard disks.
If you already are using Win XP ugraded with SP2, maybe the USB drivers need upgrading? I don't know.