How do I format a usb drive on a PC that was formatted on a Mac?

Assuming Vista or 7 (this should work on XP, 8, 8.1, and 10, as well) and that the disk is not showing up under My Computer at all: Connect your disk. Run as an Administrator. Run . Use if you need help in this program. Find the disk that corresponds to your USB disk. where is the number of the disk. Confirm that you're using the right disk with . (Warning: This command erases the disk's partition information. Any data on the disk will no longer be accessible.) . No size is needed if you want t…