This is a step-by-step guide on how to perform the formatting on your microSD card: If you are certain that the card isn’t broken, but it still cannot be read by your smartphone, you may want to format it. Proper (or improper) formatting is another common reason why microSD cards won’t work in a smartphone. If it won’t work in those other devices, then the microSD card is most probably broken. One thing you can do to test if the microSD card is broken is to insert it into other devices.

It is not uncommon for circuits on an electronic device to be damaged when it is exposed to factors like heat or water, so look for signs of any physical damage when the card isn’t working. A broken microSD card might be a reason why it won’t work on your smartphone. When dealing with errors on your smartphone and peripherals, it is important to start with the obvious problems.