Cause of error code E66
The Xbox 360 console has been modified or tampered with. This means that the console is no longer able to connect to Xbox Live, download system updates, or play new games that require system updates.
Solution for error code E66
The Xbox 360 console has been modified or tampered with. This means that the console is no longer able to connect to Xbox Live, download system updates, or play new games that require system updates