I just had the same issue, though mine didn’t crash previously like others state. Apparently the game found something wrong with the stats and the advancements files and just… got rid of them?
Having the same issue. Can confirm it also occurs in 1.21.7 candidate versions 1 and 2.
Though it doesn’t crash if the window isn’t interacted with, at least for me it only closes by clicking in the “close program” in the “not responding” thing, getting the same error code afterwards.
The thing is that it never loads, not even if left alone for hours, as I read by people having the same issue. https://www.reddit.com/r/minecraftbrasil/comments/1lei4ub/toda_vez_que_eu_to_tentando_abrir_a_1216_java/
I just noticed another user said this happened after a power outage… And now that I remember my computer had ran out of battery before this happened. So probably some files didn’t save correctly as a consequence of that.
But as someone else said, the game should keep the files instead of completely replacing them with reset ones, so that one can just fix it. I didn’t have a recent backup so now my advancements, and especially stats, are all wrong.