Memory cards, available in a variety of formats ranging from Secure Digital to Memory Sticks, are useful for storing and transferring documents. This can be done with data from computers, MP3 players and a variety of devices. Formatting a memory card on a Mac for use in digital cameras, other Macs or even PCs is done using the Disk Utility application that comes as part of the operating system.
Insert the USB plug from a memory reader into a USB port on your Mac. Insert the memory card into the card reader's memory card slot, and the card will mount on your Mac desktop.
In the Finder, select "Go" and choose "Utilities." Double-click "Disk Utility" to launch it.
Select the memory card in the Drives column. Select the "Erase" button in the top row of radio buttons. Select the format you wish to use to format the Memory Card on the Volume Format pop-up button. Use "Mac OS Extended (Journaled)" for use on Macs, and "MS-DOS (FAT)" to share the memory card with both Macs and PCs and other devices. When you have finished selecting the formatting options, click "Erase."
Type a name for the device in the Name field.
A new dialogue box will pop up in Disk Utility, asking if you are sure you wish to erase the memory card. This will permanently erase any files, so make sure you have backed up any file you wish to keep. To continue with the formatting process, click "Erase."
Once the memory card has been erased, it will mount on your Mac desktop just like any other removable drive.
Erasing an Memory Card will permanently erase any files on the disc. Back up any file you wish to keep.