GFD and Tator, this is a few days after the fact, but I just had a glitch with my SD card too. I got a Moultrie M 100 a few months back, I discussed this with Tator before I got it, great camera, so I put it up in the house to test it like Tator did, and yes my shoulder ended up looking like his from taking pictures of my other half. So then I wanted to erase those pics and did exactly what you are NOT supposed to do, used the computer to erase them. So I put the card back in the cam, took it turkey hunting this past week, put it up and had some pics on it via the counter. Tried to view them on my little Sungale viewer(this viewer will read ANY card and ANY format) and it said NO FILE PHOTOS. Brought it home, the computer said same thing, no file, put it in my old digital camera and bingo, the pics were viewable. After some research, I reformatted the card right in the old digital camera by going to the SET UP menu, took pics in the M100, and they were viewable in the Sungale viewer, the computer, and the old digital cam. So I guess the bottom line is don't use the computer to erase pics from the card.
PS: The other bottom line is if you want your shoulders to stay the way they are, don't take trail cam pics of your other half in the house!!!