I bought a D7000 as my travel/vacation body and over the last few weeks have noticed something odd. On occasion (no pattern) I will turn the camera off and the top LCD will stay on for like 10min after the camera is shut off. When I turn the camera back on the SD slot 1 icon is flashing and it dispays slot 2 as the default memory. It wont write to the card in slot 1. I have removed the card, replaced the card, formated the card and even switched the cards from slot one and two around. It may be worth mentioning that Im using a PNY Pro-Elite 16GB class 10 (35MB/s) card so I don't think thats an issue. Again it doesn't happen all the time but has happened about 3 times in the last month or so....
When I bought my D3200 I picked up a PNY Pro-Elite 16GB class 10 card and at first everything was good, then the camera was having problems recording video and then still pics. Got home and tried a couple other brand cards (sandisk and Panasonic) and all worked fine, The card was bad. took it back and then the something happened twice with replacement cards.
So I say away from PNY now. Replaced it with a SanDisk 16GB Extreme Class 10 UHS-I and it works great.
I've heard of that before. I'm on my 7th...never had that happen