Sims 3 error code 12 is an error that usually occurs when you don’t have enough memory to save the game data.
Some of the solutions to this error include upgrading your random access memory (RAM) and deleting bad save files.
Please see our in-depth walk-through solutions below.
Solution 1. Upgrade RAM/Memory and Increase Virtual Memory
Sims 3 error code 12 commonly appears when your memory is full or running at full load. Please add more RAM/memory or increase your virtual memory, it may fix the problem. See instruction below or watch it here on YouTube.
Increase Virtual Memory
Solution 2. Delete bad saved files
Sims 3 error code 12 may also occur due to bad saved files. Check your Sims 3 Saves folder to check corrupt saved files and delete them. Please see the guide below.