Hi, I have a 16GB Extreme IV card. I was able to download my pictures from it into Lightroom, but then when i put it in my Canon 7D camera I get an error message that says Card Can Not Be Accessed. It tells me to reinsert and format. I’ve tried to reformat and gets a about half way through and then this message pops up. I was able to format it in my 40D. I’ve not had this issue with any other SanDisk Cards. I bought the card in July 2010 so its just 7 months old. The 7D is my primary camera so I need to work. Does anyone have any suggestions?