How to format your SD card
Windows cannot format the entirety of the card if it has been partitioned in some way, can only handle the first partition. Also be aware that the FAT32 file system is not the most optimal. For performance reasons the best way is to use the third method and format it directly in your device.
Connect the SD card to your computer. Open the Computer window. Click the Start or Windows menu and select Computer, Find your SD card. The removable drive that appears last in the "Devices with Removable Storage" list should be the SD card that you just connected to your computer. Open the SD card to verify that it is the correct card that you want to format. Return to the Computer screen.
Open the Format tool. Right-click on the SD card and select "Format" from the menu that pops up. This will take you to the Format window. Keep “Capacity” and “Allocation unit size” set to default.
Select the file system. This is the way files are stored on the card. Different systems use different file structures. In order for the SD card to be read by any device, select FAT32 as the file system. This will enable it to be read by cameras, phones, printers, Windows, Mac, and Linux computers, and more.
Quick Format: Ticking this box formats your SD card quickly without checking the card for hardware errors. If you are formatting SD cards for the first time or suspect that they are malfunctioning you should leave this option un-ticked.
Tips: To avoid the loss of important data, you had better back up important data with easeus todo backup home in advance.