Xbox 360 system update error E66 is an error that usually occurs when the console is unable to connect to Xbox Live, download system updates, or play new games that require system updates. The console may have been modified or tampered with.
1. Do a System Update
"Xbox 360 system update error E66" usually occurs when your Xbox 360 could not establish a connection to the Xbox Live. It could be caused by a firmware which is modified or tampered with. If the firmware is modified or tampered, the Xbox 360 will be listed as banned on Xbox Live server.
The only way to update the Xbox 360 is to install a hard drive with an installed latest update. With it, the Xbox 360 will update offline upon startup. However, the console might not be able to go online due to banned in the Xbox Live. At least the system updates.
2. Clear Failed System Update
"Xbox 360 system update error E662" could also be a result of a failed system update. To solve the error, clear the failed system update, see instruction below.
To Clear Failed System Update
- Turn off Xbox 360.
- Then press and hold the Sync button (the button to sync the controller) and the Power button.
- Release the buttons when it booted up completely.
- It should clear the damage update.
- Re-update the Xbox 360.