External USB Floppy drive mounts as with drive letter B in Windows virtual machine.
How to change it to A?
Start virtual machine.
NOTE: Please take a snapshot of your virtual machine (in Parallels Desktop menu bar go to Actions > Take snapshot) before you proceed with the instruction below to be able to revert all the changes.
Press "cmd"+"R" key combination, type 'regedit' (without quotes) and Return/Enter to run Registry Editor.
Expand HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices and right click on a \DosDevices\B: entry > Rename > change it \DosDevices\A:.
- Close Registry Editor and reboot Windows.