I did a full system reset and my backup save files won't load

(important disclaimer: I bought TS3 via Steam, not Origin)

Hello! I've already asked this on the TS3 Discussions board on Steam on 20.12.16 and I haven't received any answers there so far, so I have decided to ask here as well (I'll copy-paste it from Steam)

A few days ago I did a full system reset on my PC (I backed up everything to a memory stick, including my backup TS3 files) because it was getting unusably slow and ♥♥♥♥♥♥ (please pardon my language.) After the reset, I pasted everything I backed up back to my PC and it worked fine (it's a lot faster now and I'm happy!) I installed Steam and downloaded TS3.

After the game installed, I placed my backup save files (two folders: Sunset Valley.sims3 and Sunset Valley.sims3.backup) into the empty Saves folder, as an online guide instructed. Though, once I opened the game, the household's preview image was a dotted silhouette of a group of figures, but the name of the household was still there (Kinsey).

After loading the household, the interactive loading screen ended quickly and I got the following error message: ''A serious error has occurred. It is strongly recommended that you restart your game'' or something along the lines of that (I'm trying to remember it).


Fyi I have 4 (5) expansion packs: University Life, Seasons, Pets, Ambitions (update: I now also have Generations) if that makes a difference. Before loading the backup save files I installed all the custom content and packages I backed up as well. Did that have an effect?

I am sure that the save files are not corrupted since they worked perfectly fine before I wiped my PC. I still have 2 older save file backups, in case my newest one is actually corrupted.

I have read and tried out numerous guides online on how to fix it.

Suggestions are very well appreciated, thanks! I absolutely adore this game