Team,

Today we are releasing a new Preview Alpha build at 6.00pm PDT fixing the issue with crashes in Mixer - thanks to the Insiders who reported this.
https://forums.xbox.com/en-us/thread...1-c621a10045f4

July 27th: New Preview Alpha build available (1706.170725-1700)

HOW TO GET IT
• If your console is in Instant-On mode and you have been selected to receive the update, it will download and install the update and reboot to standby.
NOTE: Once the update is available to you, you can manually begin the update by launching the Guide and navigating to All Settings > System > Updates.
• If your console hasn’t downloaded and installed the update by 1:00 AM PDT 7/28/2017 (8:00AM GMT 28/7), you will be prompted to do so at that time.
• This update has a shorter than usual window before the build becomes mandatory.

DETAILS
OS version released: rs2_release_xbox_1706.170725-1700
Available: 6:00PM PDT 7/27 (1:00AM GMT 28/7)

FIXES:

Mixer
  • Fixed an issue which could cause Mixer broadcasting to crash when a chat message is deleted.


Source: Xbox One Insiders - July 27th: New Preview Alpha build available (1706.170725-1700) : xboxone