Maintenance for the week of November 11:
• [COMPLETE] Xbox: NA and EU megaservers for patch maintenance – November 13, 4:00AM EST (9:00 UTC) - 12:00PM EST (17:00 UTC)
• [COMPLETE] PlayStation®: NA and EU megaservers for patch maintenance – November 13, 4:00AM EST (9:00 UTC) - 12:00PM EST (17:00 UTC)
The Xbox Live™ service interruption has been resolved. Thank you for your patience.
Don't click install. Wait. They know it's an issue, and they're resolving it.
Edit: If you're an idiot like me and clicked "Install" because you like shiny buttons, cancel the update and repair the launcher. That appeared to work for me.