"There was a problem loading this world."

I have a world with 3 other friends helping me build. I went to go in my world like usual and after 15 seconds of flying around the game crashes, I reboot it and go into my world and then it crashes my entire computer after getting to the "Building Terrain" part. After a few reboots of my whole computer it finally comes to the "There was a problem loading this world." screen. I cannot go off of the screen because the button to go back to the menu doesn't work so I have to restart minecraft each time. I tried renaming, copying, exporting, reinstalling minecraft but nothing works. Please help.