
If none of the previous solutions work, you can try to reset your XIAOMI Redmi Note 9 to factory settings. Reset your XIAOMI Redmi Note 9 to factory settings Then right click on the SD card reader and click on format.
#Why is my sd card slot not working Pc
You can connect the SD card to your PC then go to Computer. In order to do this, you are going to need a computer. This manipulation consists of erasing all the data it contains and therefore resetting it to zero.

The next solution is to format the SD card.

So take out the card and rub it before replacing it. Indeed, in the event that the metal plugs are dirty, it will be difficult for your mobile to ability to read SD card. It also happens from time to time that the SD card is not recognized on the XIAOMI Redmi Note 9 because it is dirty. Remove the card and replace it therefore allows you to see if the card is correctly inserted in the XIAOMI Redmi Note 9. Indeed, it sometimes happens that the small metal plugs of the card do not come into contact with that of the card reader of the mobile. The following technique is equivalent to removing and then putting the SD card back in your XIAOMI Redmi Note 9. Remove and put the SD card back into the XIAOMI Redmi Note 9

Do not hesitate to do it visually by looking if there is no scratch on the metal parts or if the card is not broken. To find out if the problem is not with the SD card, we recommend that you check the status of the SD card. Indeed, sometimes all you need is a simple restart so that everything is fine. You will probably find this a bit silly, however the 1st thing to do in this type of case is to restart your XIAOMI Redmi Note 9.
