Any SD card (or memory card) has a limited lifetime and may be broken over time. In addition, damage of the card could be due to a bug in Android operating system.
Checking a damaged SD memory card:
To check and recover the memory SD card via a computer, you will need a special device - USB Card Reader with MicroSD cards support. This device looks like an ordinary USB flash drive and sold at any computer store. The cheapest way to buy this device can be found on Ebay or AliExpress.
1. Turn off your phone, remove the battery and gently remove the SD card from the slot.
2. Insert it into the card reader and connect it to your computer. If you are lucky - the memory card is properly read by a computer.
In this case, simply copy all data from the memory card and format it. Usually photos and videos are stored in the /DCIM/ folder, but I recommend you try to download the entire contents of the SD memory card to the hard drive.
Recovery of damaged SD memory cards:
There are several options here.
1. The memory card is visible from the computer and the data has been successfully copied to your hard drive.
In this case, insert the SD memory card back into the phone, turn it on and answer "YES" when the phone will prompt to format the SD card.
Then withdraw it again, connect one to the computer and fill it backuped data which was made before.
2. The SD memory card is visible from the computer, but not all data is copied to the hard disk of a computer.
In this case, try to copy only the data you want. For example, it may be photos and videos in the /dcim/ folder.
Then you must do steps as described in the last one before that paragraph.
3. The worst option: SD memory card can not be read from the computer, the data cannot be copied.
In this case, the data will likely not be able to save. You should note that the modern versions of Android can back-up your contacts, photos and videos in a cloud.
In addition, data from corrupted SD memory cards can be restored by this software:
Smart Data Recovery
If you have any further questions, please do not hesitate to contact our help desk!