Sim's not responding

for the last few days i have started up my sims, trying to get it to load to the main menu but then the loading screen freezes and gives me the 'sims' isn't responding', then i click to shut the game down. if i try to load the game a few times i can get it to load up for me to play but i don't want to have to keep turning on and off the game until it actually works. any idea as to why my game is doing this?

 i use mods, mainly build buy/cas mods but i also have TOOL and BBB mod. not sure if any of that is effecting it or if its the sims itself.