I can see others have had this problem but they seem to feature the smart controller with the screen rather than my smartphone-used-as-the-screen RC1 setup. I need to wipe, format, my micro sd card which is now full, and cannot do so on my Mac, a Silurian Era mini which will not run anything later than High Sierra 10.12.0; not sure if this is the problem The solution is said to be to open Disc Utility, highlight the card on it, and erase, but it won’t erase because it ‘failed to erase’, no shit, Sherlock. I am currently charging up the batteries for my old DSLR to see if I can erase/format the card on the camera, and will update with the results, but apparently I will need to format the card for the drone as well, not sure how that’s done.
Can you not format it using the fly app ? Go to camera/ storage, then select the sd card you want to format 
You can format the SD card in the drone - the exact location in the menu will depend on which drone you have
I will try both those approaches, tx gentlemen, and report back. Obviously the way forward is to avoid the Mac for this job. Pardon the stupid question, is formatting the same as wiping/clearing the card so that I can put more vid/fot on it?
Drone is DJI Mini 2 SE. Card is new.
Just format as fat32 on your Mac
I’ve never had an issue
Make sure your little adapter does not have the read only tab slid up
Yep, formatting the sd card wipes all data off it and prepares it ready to be written to.
PS all Apple products seem to have connectivity to anything that isn’t made by Apple problems
I’ve tried, several times, to format as FAT32 on the Mac, but it keeps coming up with ‘failed to format card’, so that looks like a no-go and since the only remedy suggested so far is what I am doing anyway, I’m inclinded to believe the fault is with the Mac because the card, and it’s adaptor, are brand new from DJI, Lexar 128gb. and I am fairly confident they are genuine Lexar items not Amazon Chinese fakes. The read only tab is not in the locked position, but I fully understand why you asked!
I’ve successfully (I think) formatted/wiped it in my DSLR (Nikon D60, getting on a bit but still functioning perfectly; I am aware that the shutter count is mounting up, but touch wood so far…). Put the card in the drone, and fired her up along with the RC and Go Fly on the phone, and all seems well, but I need to do a test video to be sure even if I simply use the drone as a video camera and don’t fly it. I’m a bit tired now and will leave that until tomoz…
The Nikon and Mac get along fine together, incidentally, and while I need to replace the Mac, a 2011 Mini which is increasingly unable to cope with new software and apps, it is also functioning perfectly.
Thanks for your input on this, gents, I was getting nowhere with it…
Fat32 format can only be upto 4 GB, I think mine are formatted NTFS, hope that helps
The max file size is limited to 4GB not the size of the card
No DJI uses the exFAT file system
Always best to format a card in the drone using the fly app
I’ll try this next time, by which I mean after downloading the photos/videos I shoot mid-week when spring high tides coincide with sunset at my end of the Bristol Channel and whem I format the card following that. Presumably this works by connecting the charging cable to one of the usb ports on the Mac, which is then recognised as an external storage device.
If this works, I can leave the card in the drone permanently for downloading and formatting. Can it charge at the same time? The drone has to be turned on as does the RC and the iPhone connected to the RC as if you were going to fly it, presumably.
Negative, just the drone