I bought a micro SD card, and it showed up normally when I inserted it into my Mac. However, after I put the SD card into my dash cam, formatted it, and recorded a video, it no longer shows up when I insert it back into my Mac.
I have the same issue before. It happens because the micro SD card was formatted in the dash cam using a file system that might not be compatible with Mac, making it unrecognizable. In this case, if you do not need to make the card to a specific file system, you can use Disk Utility to reformat it into a Mac-compatible format, such as exFAT.
If you want to save the videos from the dashcam, it’s better to recover the data using recovery software before reformatting. I previously used iBoysoft Data Recovery for Mac, a professional data recovery tool that can help recover videos from unrecognized SD cards. Download iBoysoft Data Recovery for Mac and have a try.