Why wont my gameload?

I have a relatively new world that whenever I try to load it the game crashes. I've tried making new worlds, they all load but then when I leave them and try to get back in they crash, I've tried to increase the allocated ram all the way up ro 12, but it still doesn't work. Do any of you guys have any ideas for me? I hope you do because I've really enjoyed watching people play the mod in the past and would like to enjoy it myself.