Quite a few Chinese dashcams you have to format the SD card in the dashcam itself, it still works fine with a PC.
The other problem you may have is that it is a "hooky" SD card, something like a 2GB card that pretends to be a 32GB, there's a lot of scams like that, sometimes they even seem to format ok and report free space back ok but they will never store the full amount correctly. I stuff a load of pictures on them then check that windows manages to create the thumbnails for all the files which is quick and easy check. I've had my money back on a fair number of pen drives but been lucky on SD cards.
