Disable write-protection on Micro SD

Dust out your adapter. The sensor inside of it may be dirty and not recognizing the position of the switch.

I would also try another SD<->MicroSD adapter.

If you still experience problems, try putting a questionable SD card inside of a phone. I'd say if you get 2 or 3 cards that work fine in a phone, you should replace your USB card reader, see if maybe there is an issue with your USB connection, or use Linux to perform the task if possible which tends to behave a lot better regarding removal/insertion of USB devices, disks, and volumes than Windows (OSX also likely behaves a lot better).

If you find that the MicroSD cards are actually write protected (which should not be possible - the host/card reader is responsible for implementing the write protection and switch sensing, not the microcontroller in the card), I'd keep the bad ones and demand a refund.