1 Insert your SanDisk 8GB memory card into a card reader connected to your computer.
2 Double-click "Macintosh HD" on your desktop.
3 Click on the "Applications" folder, then the "Utilities" folder.
4 Double-click "Disk Utility". Look on the left side to locate the drive that says "SanDisk.
5 Select the capacity of the drive on the left side of the window. The capacity will state "8GB" or "8,388,608 kilobytes." Click on the "Erase" tab to format the memory card. When you see "SanDisk" listed as the device's name, the capacity will be located above. You need to select the capacity and not the device.
6 Select the appropriate "Volume Format." Under the "Volume Format" button, select the format you wish to use. Select "Mac OS Extended" if the SanDisk 8GB will only be used on Macs, or "MS-DOS (FAT)" if you will share the card between a Mac and PC. Select "Erase" to complete the format of your SanDisk 8GB memory card.