Memory Card Error
Before using a new memory card or a card formatted in another device, you should format the card with this camera.
If you do receive a Memory Card Error, try a different Memory Card before proceeding or if you do not have a card, continue.
Perform formatting in theses cases: [Memory Card Error] is displayed, the camera is not working correctly, card images reading/writing is slower, continuous shooting is slower, or movie recording suddenly stops.
Formatting ERASES all the data on a memory card. Before formatting, copy images on the memory card to a computer, or take other steps to back them up
If neither of the above suggestions corrects the situation, we suggest the following actions:
Check our Frequently Asked Questions for more information- http://www.usa.canon.com/cusa/support/consumer/digital_cameras/powershot_g_series/powershot_g15?CMD=MIXED_SEARCH&mName=PowerShot+G15&mType=PowerShot+G+Series&pageKeyCode=ekbresults&searchString=memory+card+error&BASIC_SEARCH_CURRENT_TOPIC_ID=3570&BASIC_SEARCH_CURRENT_TOPIC_TYPE=0&RESULTS=RELEVANCE&RELEVANCE_START=1&RELEVANCE_COUNT=25&CONFIGURATION=1011&PARTITION_ID=1&TIMEZONE_OFFSET=null&USERTYPE=1&isSecure=false
Contact our Email Support for further assistance -
http://www.usa.canon.com/cusa/support/consumer/digital_cameras/powershot_g_series/powershot_g15/form_display/support_by_kb_email