I formatted a 64 & 16 GB card in the Mavic and both of them seemed to play nice with the computer so the problem is intermittant I guess as it has happened before on & off. I never ever have any problem whatsoever with external drives, thumb drives or SD cards. Only cards I have used in the Mavic. I noticed the cards are formatted exFAT and I should look into why or how that could malfunction periodically. Or maybe the format in the Mavic isn't done properly. I do not think it's cards as I have several fast new top brand cards and they all have done this at one time or another. Reading a couple posts right off the bat:
"I strongly prefer to format my cards in my desktop computer to avoid the "card not formatted" error that frequently occurs with device-formatted cards.I usually try to format and name my memory cards on my PC or Mac. The reason being, sometimes, when you initially format memory cards on a device, they have a hard time being seen on a Mac or PC when you plug them in."
A possible solution, I'm going to format on the computer in exFAT so if there is an issue hopefully the drone will flag it and prevent recording then not being able to download the file
Also this solution if the card won't read (if it was formatted in the Mavic and won't read)
Download
:
1. Plugin Mavic Air to computer via USB-C cable
2. Find the DCIM folder with the images/video
3. Copy the media data to local computer disk
4. Eject the disks (safely remove)
5. Unplug the drone from the computer
Reformat SD card on computer:
1. Plug SD card into the computer via the card adapter.
2. Format the disk in OSX "Disk Utility" > "Erase"
3. Important: choose file system type of "ExFat"
4. Give the SD card a label, like "MavicAirSD1"
5. Done!