The issue emerges if the e-mail linked to one's Windows Live ID, such as Hotmail, expires. Windows Live Hotmail accounts are disabled after 120 days of inactivity.

Upon its expiration, the e-mail address is deleted along with any linked Xbox Live accounts, apparently leaving holders unable to change the linked Windows Live ID or purchase an Xbox Live Gold subscription in order to play online.

However, they are still able to download items from the Xbox Live Marketplace.

Microsoft is investigating the problem, but at present, the only solution is to make a new Xbox Live account using your "preferred email address"--which leaves users starting anew without their friends list, achievements, and history of downloaded content.