- Insert your SD card into your computer
- If the SD card has any files and folders on it, copy everything to a folder on your computer
- Run the Disk Utility app
- In the top-left "View" menu, choose "Show All Devices"
- Select your SD card in the left panel
Make sure you choose the correct device, otherwise you might accidentally erase the wrong drive! - Click "Erase" at the top
- Enter anything for "Name"
- Ensure that "Format" is set to "MS-DOS (FAT)"
- Ensure that "Scheme" is set to "Master Boot Record"
- If "Scheme" does not appear, click "Cancel" and make sure to choose the device instead of a volume
- Click "Erase"
- Wait for the format to finish
- Click "Close"
- If the SD card had any files and folders on it before the format, copy everything back from your computer