How to Reformat an SD Card in OS X

By Julius Vandersteen

An SD (Secure Digital) card is a small memory storage unit that people typically use to store files such as pictures and videos shot with a cell phone or digital camera, or to add music to a portable MP3 player. An SD card might be formatted by a particular device, or by a computer. If you need to reformat an SD card with a Mac running OS X, you can easily do so with Disk Utility, a free utility that Apple installs on every Mac.

Step 1

Slide the SD card's slider to the unlocked position if it is not already unlocked. A locked SD card can't be erased or reformatted. See the manufacturer's instructions for details on the location of the SD card's slider.

Step 2

Insert the SD card into the SD slot on the Mac, or into an SD card reader that is plugged into a USB port on the Mac. The SD card will mount on the desktop.

Step 3

Click "Applications" in the Dock, then click "Utilities," and then click Disk Utility."

Step 4

Click on the icon of the SD card in the left side of the Disk Utility window.

Step 5

Click the "Erase" tab.

Step 6

Click the "Format" pull-down menu to select a format for the SD card, such as "Mac OS Extended" to use the card with a Mac, or "MS-DOS (FAT) to use with both a Mac and a PC or another device that may require MS-DOS formatted SD cards, such as a digital camera.

Step 7

Click "Erase." The SD card will now be reformatted according to the setting you chose.

Step 8

Right-click on the icon of the SD card on the desktop when you have finished formatting it, and then remove it from the slot or the card reader.