Reasons to Back Up Your Data
Backing up save data is wise to ensure that countless hours spent in-game are never lost. To avoid corrupted save data, make sure you never remove the memory card or turn the GameCube off while in the process of saving, copying or moving data. Also remember to be careful when using devices such as a Pro Action Replay, as certain manipulations of the game's code can result in corrupted saves. Before extensively using such devices, it is best to make backups of all of your saved games.
Accessing and Copying Your Data
Insert the memory card with the saved data into slot A of the GameCube and a blank memory card into slot B. Turn on the console with no disc in the disc tray and access the memory cards. Select the save file to be copied and press A. When presented with the options of copying, moving or deleting the file, choose to copy it. The system will ask you to confirm. Be careful not to delete your file, and remember that moving it moves it to the second memory card but deletes it from the first. Once all of the desired data has been copied, the memory card in slot B can remain in the system itself or within in any official GameCube game's case, as they all feature a small housing for memory cards.
USB Memory Card Adapters
For those looking to save their data onto their computer's hard drive or swap data with other players, USB memory card adapters are available online. Adapters are useful for people who manage a larger amount of saved data, as many GameCube memory cards only offer a fairly limited storage space.
Memory Cards and Wii Compatability
Also note that while GameCube memory cards and games are compatible with the Nintendo Wii, saved data from GameCube games cannot be transferred from a GameCube memory card to the Wii's internal memory. Accordingly, two memory cards will still be required to perform a backup.