what Sandarcher said and if you want to see if you can help it you can try these once you remove a mod the cache files need to be cleared out and the same if you add a mod
to delete the cach files go to electronic arts/the sims 3/
•CasPartCache.package
•compositorCache.package
•scriptCache.package
•simCompositorCache.package
•socialCache.package.package
it's safe to delete these files as a new ones will regenerate
then go to electronicsarts/thesims3/saves open that save folder and see if any files there end in .bad if they do delete them as they are no good and a waste of space THEN the save that is giving you an issue copy the save file and the backup file of that save to the desktop for now to have a backup of the game
then in the saves folder rename the backup to something simple like for example TEST.sims3 launch your game and and find the renamed save game in the main menu TEST and launch it to play , play for a few mins to let the game settle down a bit once it ettles i would also try the reset all Sims cheat too in case a stuck Sims somewhere in the world
to reset all sims ctrl+shift+c hold all 3 together in the menu bar that appears at the top of the screen type in resetsim * (inculding the * hit enter ) this will reset all Sims including your own make sure your own aren't doing anything important cancel their action q
