So you did something with your SD card (other than its normal usage) and now it’s not showing full storage space.
For instance, something went wrong while I was installing NOOBS (an operating system for raspberry pi) on micro SD card and in that process I lost 90 percent of my storage. The first thing to do here is using Windows inbuilt format tool. But that didn’t help either.
There can be several reasons for this — either your SD is damaged or windows is only showing partition that it understand. So even though the rest may still be there, you can’t see or use it.
There is a simple solution to this problem. Download SDcardFormater from here. This small software is design especially for SD card that uses SD/SDHC/SDXC standards and is available for windows and mac.
Though the product page do not show support for windows 10 but download it anyway. It worked for me.
Once downloaded, install and run it on your computer. Then select the partition of your memory card. Under options select format type quick and format size adjustment ON. And format your device.
That’s it. You will get your lost SD card size back.