Are you still experiencing the problem? I'm in the same situation; my Windows 11 is completely up to date, and I'm getting the error 16 codes every time I try to save, so I can't progress in the game. This is so frustrating.
@Mayaaleah and @WingedSnek , I am trying to research this issue to see if there are other solutions to try. One suggested going into your TSM saves and try removing the word "backup".
Ok, found something else to try for Windows 11. It was for Sims 3, but they share the same game architecture. I found this on Reddit.
The error appears to be related to writing a file in the specific Documents Directory. The person who wrote this said they changed directory and tested several times and it appeared to work. The directory in question is the one where the game stores its saved files and if you use mods, the mods could be found there. Now, you can either store these files on an external drive or your Desktop. Do not use One Drive/the Cloud as this is probably what can cause the error as well as the game doesn't normally read saves well from the Cloud.
You will need to change the command prompts to create a symbolic link which will then tell the game where to store and read the saved games from. You'll need to research how to create this symbolic link, but it could be a solution to the error.
I cannot guarntee this will work, but at least it is something to try. Please let us know if this seems to work.
