I hadn't had any issues until today, but it was my own doing. I had a 256mb card in my phone and wanted to see how many pictures my DSLR would be able to take with that card instead of the PQI 1GB card that was in it. I took out the card from my phone while it was on, whoops. When I put it back in it said "memory card is an unrecognized format, formatting the card will result in loss of all data on the card, reformat now?" So then I remembered that my Motorola E816 uses the same size card, the 256mb card actually came out of that phone and didn't require me to format it when I first put it into the Sync. So I decided to put the card in my Moto phone to see if it would recognize it, it did. I turned off the Sync and put the card back in and turned it on, same error message.

To fix the problem I put the card back in my Moto phone, took a picture and saved it to the card, then put the card back into the sync and now all is well!

I know some of you have had issues with your memory cards so I just thought I'd pass this along to see if it helps you at all.