I managed to get my dad into minecraft a while back and have more recently gotten him into modded. I have been playing offline in our world a lot recently and have built a nice house from a guide. Last night was when we were going to play together but I was getting ridiculous amounts of lag. I save and quit as I was hoping relaunching would fix the problem. As I hit quit game my computer froze on the title screen. It showed no signs of unfreezing after a while, so I manually rebooted it. I reopened the singleplayer selection menu, and it did not show up in the list. I checked the saves file and it still showed up there. Does anyone know what happened and how to fix it? I can provide the file download if necessary. The modpack being used was OhGaming's craft crazy on the technic platform. http://goo.gl/CVXPJl Any help is appreciated.