How to Format a USB Pen Drive on a Macby Christopher Capelle ; Updated September 28, 2017
One of the most useful devices of the computer age is the pen, or flash, drive. With the ability to hold a surprisingly large amount of data for its size, flash drives save time by allowing users to quickly transfer data between computers. Previously, the two computers had to be networked, or users had to revert to clunky methods, such as attaching a hard drive to the computer or burning the files onto a CD. While flash drives are universal, some Mac computers are unable to read flash drives that have been formatted in a particular way, so learning how to properly format your pen drive is paramount.
Plug the USB drive into the Mac. Avoid plugging it into a USB hub or the USB port on a Mac keyboard.
Click the "Finder," choose "Applications," choose "Utilities and launch the Drive Utility. This software is part of the Mac operating system.
Select the drive in the left pane. In the Name field, type a name for the pen drive.
Select the "Erase" tab in Disk Utility, making sure the flash drive is selected.
Choose the desired format that you want the pen drive to have. If you’re planning to use it with both a Mac and a PC, select "MS-DOS (Fat)," which will allow it to be read by both Windows and Macintosh computers. If you’re planning only to use it for Macs, select "Mac OS Extended (Journaled)."
Click on the "Erase…" button. This will erase all the data on the pen drive, so back up any data you want to save before getting to this point.
Eject the pen drive, either by dragging it into the trash or by using the eject button -- the triangle icon -- in the Finder window.
Formatting a drive deletes all data on the drive. Back up your data before you format a drive.