Hi  my current Mavic 2 Pro which I received after crashing the old one. (Thanks DJI!) keeps getting this error when I try to transfer files from the SD card to my PC.
"You need to format the disk in drive G before you can use it"  Sorry cannot seem to upload a picture.  I get this error whether or not I try to access via the drone connected or just the sd card.  

It is an approved SD card and the wierd thing is it contains earlier videos/photos on the card that downloaded fine the last time I flew it.  I had not formatted it since then or changed any of the settings.   

If I put the SD card from the drone into the smart controller, it will read the photos/videos fine.  I have tried different cards, re uploaded the firmware to the drone and controller, but no luck.

This is an intermittant problem and very frustrating as I am flying for clients.   Any help would be greatly appreciated.

Thanks!
Hi thanks to Labroides,  I realized I did not include the fact that this has happened on multiple cards.

The obvious suggestion is to try other cards.

True I should have included that it has happened on multiple cards

I just had this happen with the drone's internal storage.  Drives D and F would appear, but then D would disconnect and F was not assessable (possibly the empty external card slot).  In an administrator command prompt I was able to run a CHKDSK D: /f, despite the D drive not even showing up in Windows.  Within seconds, the drive appeared in Windows and was usable.  
Good lesson for me to run a format on internal/external media before flying and taking important photos.  It under the camera settings in the DJI Fly app.

MikeFlorida Posted at 5-7 11:07
I just had this happen with the drone's internal storage.  Drives D and F would appear, but then D would disconnect and F was not assessable (possibly the empty external card slot).  In an administrator command prompt I was able to run a CHKDSK D: /f, despite the D drive not even showing up in Windows.  Within seconds, the drive appeared in Windows and was usable.  
Good lesson for me to run a format on internal/external media before flying and taking important photos.  It under the camera settings in the DJI Fly app.

I have had this happen several times in a row when using the internal storage, despite formatting between flights... which is disappointing.  I always do the "safe eject" in Windows as well before disconnecting from the drone.  I tried adding a a new external micro-SD card and when that was formatted it came up with a warning indicating it was slow and degradation was a possibility.  

Seems I am stuck with getting format required errors and potentially not being able to resolve this with a CHKDSK, resulting in data loss.  vs.  Using a new media card that is reporting data transfer is slow, also potentially affecting my stored photos.