How to Format an SD Card to FAT32by Aaron Parson
Every computer storage device, whether an SD card or a hard drive, uses a file system that affects the behind-the-scenes mechanisms computers use to read and write to the card. Two common file systems for SD cards, FAT (File Allocation Table) and FAT32, differ in maximum capacity and compatibility. Many small SD cards use FAT by default, but if you need to switch to FAT32 for compatibility, Windows 7 or 8 can reformat the card, after you move your files off of it -- formatting erases all files on a card.
Press Windows-E to open the Computer window. Right-click your SD card in the window and choose Format.
Before proceeding any further, make sure you've copied or moved everything off the card that you want to keep. Reformatting a card wipes its contents.
Pick FAT32 from the File System menu.
In addition to FAT and FAT32, the menu offers exFAT, which supports even higher maximum capacities than FAT32's 32GB limit, but might not be compatible with your devices that use FAT32 SD cards. The other option, NTFS (New Technology File System), is usually only used for Windows hard drives -- cards formatted with NTFS won't work in most devices.
Leave the other options set to their defaults, except for optionally unchecking Quick Format. Quick formatting an SD card takes less time, but may not detect some problems with your SD card. Unless you're in a hurry, uncheck the option to run the check and make sure your card is in good condition.
Finally, click Start to begin the reformat.
Click OK to confirm that you've copied your files off the card and proceed with the format.
Click OK when the format finishes. You can now use your SD card. Before pulling the card out, remember to eject it safely.