The Xbox One Experience update as part of the Preview Program seems to be having a few minor issues that are getting resolved soon.

The Xbox One Experience hangs when updated at around 80%, interim fix has you pull the power.

　　“System Update Hangs: A huge thank you to the community over the past 24hours as we encountered a system update error when the system upgrade hangs at 80%. Engineering has determined the problem from your experiences and a fix is underway.”

　　In addition to that, they've issued advice for a temporary fix that should allow those beta testers to get in on the action, past the installation phase and start contributing some valuable feedback. The fix? Unplug it from the wall actually!

　　“In the interim any user that encounters the system update hanging at 60-80% please do the following:

　　Pull physical power (yes, I really mean pull the cable).

　　Once the console is powered back on, it will appear to complete an update, then land on a System Update available screen.

　　Attempt to take the update again, if it hangs a hard reboot may be required again and try again. We have seen that 3 reboots can complete.”

　　As we all know, participating in a beta program tends to have its own set of risks involved. When involved in it one, active participation and reporting of bugs is critical to getting things fixed. It can be great for early adopters, though you may not be satisfied with the experience, and inevitably someone will complain, not really understanding what the Xbox One Preview Program actually is intended to deliver.