this had me wondering what the heck has happened

[realspeed]

got the CArd message flashing on the top screen of my Nikon D810.
First thought it was a fake sandisk card.
being duel slot first removed the sd card and top screen back to normal so the CF card was ok, must be the SD card.
So in the camera went the SD card alone and the error flashed up again and it is a 64 Gb card. damn more expense for a new card

Not so, somehow the locking slide on the edge of the SD card had gone into the lock position. All it needed was returned to the use position and everything back as it should be

just thought it worth a mention if it happens to you

 

[sirch]

Happens to me quite a lot but both the cameras I use frequently (Canon and Olympus) put up a "card locked" type message.

 

[4wd]

It happens, make sure the edge of the card isn't breaking up though if you frequently pull it in and out.
I had one a thin strip cracked off the side so it didn't locate properly, it could have been nasty if the bits or card had jammed inside - a sandisk too.
They don't particularly deserve their assumed market leading image.

 

[Cagey75]

Yup, have had it happen me many times, the older a card gets the easier it is to knock it into lock accidentally

 

[spudhead]

same thing on my a99ii sometimes