You will know when an SD card gets corrupted when you see messages in Windows or on your phone like this:
- SD card is damaged. Try reformatting it
- SD card is not formatted do you want to format it now
- Disk is write protected
You may also encounter problems where files saved on the SD card get lost without being deleted, no stored files are displayed when you connect it to PC, you may be unable to copy the photos or videos on SD card and may get a message saying the disk is "write-protected".
Reasons why SD Cards Get Corrupt
SD cards can get corrupt for a number of reasons, but the most likely cause is from removing or unplugging the card without properly unmounting it, or from power loss during write operations. Both of these can corrupt the filesystem.
If you have a cheap unbranded SD card the quality is more than likely poor. Cheaper cards use cheap components which have much lower tolerance for failure, and some even offer lower capacity than advertised and use software trickery to fool you into thinking the card is actually the advertised capacity. Always use cards from a well-known manufacturer such as Sandisk, Kingston, Samsung, Lexar, Toshiba, and a reputable seller.
How to Fix Corrupt SD Card
Your first check for fixing corrupt SD cards is to reboot your phone. This should eliminate software errors such as bad memory or incorrectly loaded drivers.
If a reboot does not fix the SD card corruption it can still be something simple such as a loose or incorrectly installed card. Try powering off the phone and remove the card. Check to make sure that the contacts are clean and there is no physical damage. Also check the socket is dust and hair free. Reinsert the card and power on the smartphone. Check to see if you can read the SD card now.
If these tips have not enabled you to read the SD card, it is possible that the problem is caused by the mobile phone. You can power off the phone and try to use the SD card on a Windows PC with an SD card reader or USB adaptor. From here you can see if you can copy the files off the SD Card.
If you cannot copy all the files off using this method then there would appear to be a problem with the card filesystem. You can try using the
chkdsk command to repair the filesystem. This assumes that your SD card was mounted as drive D:. It may be different on your computer, so change the drive letter accordingly.
chkdsk d: /f
If this doesn't work you may need to try specialist data recovery software to scan and recover photos and documents. DiskDigger can undelete and recover lost photos and images from your memory card or internal memory. Primo Android Data Recovery requires root access but ensures a high rate of recovery.
If you still cannot recover your files your SD card may be unrecoverable. You can try and format the card which will reinitialise the filesystem and reset the contents. You can then test reading and writing again by saving a few files and reading them back in. If this doesn't work then the SD card had almost certainly become damaged beyond repair and needs replacing.