My Mac Won't Read My USB Flash Drive

By Greyson Ferguson

Format any removable device so it functions on a Mac computer system.
i cd rom inserted into laptop image by Egor Ukoloff from

USB flash drives are used to transport data from one computer system to another. However, if you are attempting to use the flash drive on a Mac computer and the system is not reading or copying over information, you need to fix the issue, which is likely due to the formatting of the flash drive, as some devices are not set up to run on Mac computers (initially). Thankfully, it is possible to format the flash drive so it is easily read on both PC and Mac computer systems.

Step 1

Back up all the information on the USB flash drive onto a Windows-based computer before formatting the drive (once you format the drive all data is removed). Connect the flash drive to the computer, select "Start," "(My) Computer," double-click the removable device icon and click-and-drag the files from the open drive onto the computer.

Step 2

Connect the flash drive to a USB port on the Mac computer.

Step 3

Click the "Finder" icon in the lower, left corner of the desktop, then type "Disk Utility" into the search bar. Double-click the Disk Utility option that appears on the screen for the USB.

Step 4

Select the "Disk Partition" option, then choose "Mac Partition" as the format you want to format in (this allows you to use the device on both Windows and Mac computers). Click "OK" and the USB flash drive is formatted. Once complete, connect the device to the computer, copy all the files back onto the device and you are all set to begin using the USB flash drive on your Mac computer.