Consistent crashing when trying to open existing world

Good morning. I have a world that I really enjoy that I am having issues with. System keeps kicking me out as I am trying to load world. I have to restart each time this happens. I have not been able to access this world in days. This happens at screen generating world, building terrain. In addition, when I have been on this world, sometimes my scenery builds extremely slow. I do not have this issue with the two other worlds that I have.