I have a Canon PowerShot A510
using a Kingston 2GB microSD
card with an SD adapter.
The SD card worked perfectly until I formatted the card in my Mac. I formatted it with MS-DOS Fat file system. Now, when I turn the camera on with this card, it doesn't recognize it, doesn't specify how many pictures it can take with the current settings, and doesn't respond to any button, mode change, the shutter or even the turn off button.
The only way to turn the camera off is taking the batteries out. When I try my older SD cards of 16 and 256 MB, it works fine. If I format the card, the Mac reads it perfectly; when I put it in the camera, it encounters the problem above; after which when I put it back in the Mac it doesn't recognize it anymore. It seems like the camera tried to format it, but left it in an inconsistent format or state. I then have to format it again on the Mac to use it.
PS: As this is almost unrelated to the art of taking pictures, excuse me if it's off-topic.