Forum Discussion
maryebrumett The most common cause of this is indeed a bad mod or cc item, and normally there's no substitute for testing. However, two somewhat-popular mods can cause this, so maybe you'll get lucky. The first is NRaas Cupcake if the bakery set from the Sims 3 Store is NOT also installed. The other is NRaas MasterController's Progression add-on if the base MC and StoryProgression modules are not both present. So check your Mods folder for those.
Aside from that, test whether the game runs without your Mods folder present. If it does, test one of the mods you brought over to make sure the whole collection isn't corrupted. (In that case, you could transfer them again, zipping the folder first to protect the files.) If one mod is fine, the fastest way to find the problem is the 50/50 method.
https://modthesims.info/wiki.php?title=Game_Help:Finding_Problem_Custom_Content#The_50.25_Method