I was going to use my camera and a notification came telling me to install an sd card. Needless to say, I wasn't able to take a pic. I shut down the camera, restarted it, and it gave me the same notification.
Eventually, I shut down the phone, checked to see that the card was there (it was), turned the phone back on, and the camera worked.
Just to add, I haven't removed the card in a very long time and I have yet to plug my droid to my pc.
Anyone have any ideas as to why the droid didn't recognize the presence of the card? All my photos saved to the card were viewable.