Okay guys. ive finally found a solution. ive tested it, and its worked for my game, hopefully it will work for yours.
Go to Documents/Electronic Arts/The Sims 4/cache and delete all the cache files.
then go into the saves folder and delete all of the saves.
Then go into the "scratch" folder within the "saves" folder and delete all the files which had the words "save game" in it.
You will need to create a new game, then save it, exit the game and then relaunch Sims 4.
