Re: [online service error (0x00100500)](/topic/95932/online-service-error-0x00100500) I have the exact same problem and error code. It can happen at any time for unknown reasons. It appears when I try to save the game. I can usually tell the server is not working when I do not have the option to save over an older save. The only option you have is to save and if save it does not work and you will lose all progress back to the last time you saved with the option to save over an old save was available (if the option is available you can do a new save). The strange part is you can continue to play, but nothing is saved. If you log out and then log back in you return to the spot of your last real save. The only way to clear the online error is to logout and hardboot the Xbox console. Even then it will eventually happen again. This has been happening for at least the last week.