- 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
guiformat.exe
- Select your SD card’s drive letter for "Drive"
Make sure you choose the correct drive letter, otherwise you might accidentally erase the wrong drive! - Select a size for "Allocation unit size"
- If the SD card is 64GB, choose 32768
- If the SD card is larger than 64GB, choose 65536
- Enter anything for "Volume label"
- Ensure that "Quick Format" is selected
- Click "Start"
- Click "OK"
- 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
Common errors with guiformat
Failed to open device: GetLastError()=32
Close everything that may be using the SD card, such as any File Explorer windows.