OK like a dumb ass I just did the IMU and compass calibration. This was after I was in the learning stage when everything was working just fine,
I went into the camerea settings and tried a format, error. On the main screen at the top it says SD card unknown error also the camera
indicator light starts of flashing green thengoes to a flashing red error. The problem is that I have 2 Sandisk cards that were working fine
for the last 4 weeks. They will not format after I calibrated the drone and I did try using the PC formating for NTSC. How can a calibration
screwup my card reader? All this occured after successful flight and my calibration in the house. OK just tried a brand new SD card, so that
3 now all not recognized.

OK, OK I got it. Fought all night with this error. Place card in your PC select default allocation size and exFAT.

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I have a phantom 4 pro plus and keep getting the same error message. Sd card unknown error. Card is formatted and still nothing even with different cards? I'm new to this and would appreciate any advice given.