I have 2 64gb Micro SD class 10 cards that I use for my Vantrue X2 car dvr , one is a SanDisk Ultra 64GB and the other is Kingston 64 GB. After experiencing some issues with the camera not recognising the speed of the card, the manufacturer suggested formatting the cards to FAT32 with the HP FAT32 formatting software.
I downloaded the software here and tried to format the first card, I got an error saying the card cannot be formatted. I tried to access the card via file explorer and go the message please insert usb device. I tried with the second card but used a different usb adapter and had the same issue.
After looking around for a solution I found this software HDD LLF (low level formatter) which formats the card and got the card working again. After using the software, run a full format (not quick format) via the standard windows formatting option.