If you are unable to write to your MicroSD card, there are two possible causes. If you're using a MicroSD to SD card adapter, it has a built-in lock feature that prevents accidental erasure. As a side effect, this protective feature also prevents you from writing to the card. If you can read from the device, but not write to it, this lock is the most likely culprit. However, data on the card can also be corrupted and prevent reading from or writing to the device. If that's the case, you will need to format the card and start over.
Adapter Lock
Step 1
Remove the card adapter, along with the MicroSD card, from your card reader.
Step 2
Slide the locking switch to the unlocked position. If your card adapter is not labeled, the unlocked position is closest to the front of the card where the metallic contacts reside. Insert the card adapter into the reader and try again; if you still cannot write to the card, continue reading.
Step 3
Remove the card adapter again and toggle between the locked and unlocked position three times. Stay on the locked position for 30 seconds and then switch it to the unlocked position. Try the card again.
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