Simply erasing, or deleting, images on your memory cards don’t fully clear the cards of leftover data.
Instead, it’s better to get in the habit of formatting your cards. Formatting is a more complete way of clearing old files from your card and can reduce the risk of data corruption.
You may format the cards by the cam itself or by the Format tool.
Usually, if the cam keeps giving you a "Please format the card "error, we suggest formatting the Micro SD card by computer.
Please download the GUIFormat tool from the attachment. after downloading it, it will recognize the SD card if you plug a card reader with the card into the computer, then you can directly click the "start". if you want to deeply format the SD card, please don't choose the quick format.
You can refer to this when choosing a new card.