So this happens to me yesterday and got me worried. I booted-up my Xbox Series X and got stuck on boot, staring at the Xbox logo and him staring back at me… It’s pretty hot right now, so I thought I had let it run for too long or something was busted.
I searched online for a fix and just used the Factory reset. On Xbox Series X, you have to hold the eject button and sync button at the same time right after turning it on. It launches the system recovery process and then it’s pretty straight forward. But then, it happened again when I rebooted it. Stuck on the Xbox logo.
Then I remembered that I had an update recently, so I went to the Xbox Insider reddit and saw that I wasn’t alone. I was relieved !
Devs are aware of the problem and are investigating. For the moment, unregistering from alpha fix this or changing from alpha to beta is enough. It’s one other factory reset process to get through, but at least you’re fine after that.