The solution is explicitly to map the USB drive to a drive letter and here's how that's done...
- Right-click "My Computer", then select "Manage"
- On the left-hand side, locate "Storage".
- Under that will be "Disk Management"... select that.
- This will show your computers drives and partitions.
- Locate & right-click the USB drive you have installed, then select "Change Drive Letter and Paths..."
- On the dialog box, find & select "Change..." then select your drive letter of choice from the combo box and press OK. I use Z.
You'll get a warning message, but you can ignore it. Nothing is running off that USB device (since it didn'tt map correctly already). You'll now be back to the Disk Management dialogue, and your new drive letter is showing for your USB drive. Close this dialogue -- you're done.
If you now uninstall the USB drive, and then reinstall it, it will come back up as the same drive letter as you assigned.