Hey Everyone,
I have had my Inspire 2 since January.  Overall it has been pretty good and I fly it lots. I would get the odd IMU or Compass error so I try to calibrate before every flight.

I had an issue the other day.  I flew 1 site and everything was good.  The next site I was flying I got the Main Controller Data Error.  The videos from that flight were saved on the MicroSD card but the previous sites were gone.  The error said to restart and if it persists, contact DJI.  It did persist and I have sent a ticket in but not heard anything for a few days. But now the "record" of warnings does not have this particular warning showing on it.

I went home and hooked everything up and then was getting Inconsistent Firmware (which has happend a few times for weird reasons - different battery sets?) so I updated whatever needed updating and then I was not getting the Main Controller Data Error anymore when I restarted. I then went and flew another site and low and behold no data recorded on the MicroSD (yes, inserted properly).
Fortunately both sites videos were cached on the DJI Go 4 App so I was able to have some record of the videos at least.

I don't know what the heck but it is frustrating because crop is coming off the fields and now is the time I can get some accurate elevation maps, etc.   

"MC data error" indicates the SD card (not the Micro SD card that used to record pictures and videos but the card in main controller) is full, but it will not affect the flight. Reboot the aircraft to delete all the flight data will be fine. If the error persists after rebooting and firmware updating, the aircraft will need to be sent in for repair.
For the Micro SD card that used to record pictures and videos, please format it and try again.