The Muvi K-Series will take a few seconds to register the microSD card when the camera turns on. If the message does not disappear after a few seconds please try the following:
1. Format the microSD card in a computer, then reinsert the card into the Muvi.
2. Try using a different microSD card with the Muvi.
3. Factory reset the Muvi using the option in the menu.
4. Update the firmware on your Muvi using instructions and download at Downloads