Hello,

When I opened my Minecraft, selected single player, created a new world, i selected more world options, went and opened "Cities" in the top right of the screen, I enabled Cities by clicking the 'Disabled' button, and then clicked 'Customize'. Once I did this, Minecraft closed completely and then I received this crash report. I hope that what i have given you is contextual enough. I appreciate that my case is being looked into. Thank you.

crash-2021-03-14_07.58.34-client.txt

Thanks for reporting. Lucky for you you don't want to actually customize the 'disabled' profile :-)
In the future I will make the customize button unavailable when the profile is disabled