@raemariek
Are you sure that those sims you cannot see were not saved as CC? You do not need to have CC to get such an effect. Just sometimes have some mod in the game is enough. Try enabling the "show modified objects" option in the library.
@raemariek
Try doing the factory reset of your game folder. It can force the game to read your Tray folder.
You will lose nothing.
Go to menu Start/ Documents/ElectronicArts - inside will be The Sims4 folder
Step 1. Rename The Sims4 folder to "The Sims4 old"
Step 2. Fix the game in Origin
Origin/Library - right click on TS4 - option "Repair game"
You have to wait until Origin will fix all packs, not only the base game.
Step 3. Turn on the game - a new game folder will be created and you will have two - one old, one new
Step 4. Check if you still have this problem in the newly created game folder -- save a random sim to the library.
If the problem disappeared
Step 5. Delete in the new game folder following folders:
"saves" and Tray.
Step 6. Go to "The Sims 4 old" folder and copy - your "saves " folder.
Step. 7, Paste this folder in a newly created game folder.
Step 8. Do the same with Tray folder
Step 9. Copy and paste your mods and CC from old mods folder to the new one. First, copy the scripts mods every time checking if the game is working properly. If you have a lot of CC try 50/50 method
If you do not have mods or CC, skip this step.
Step. 10. If all is OK - delete The Sims4 old folder. Now you will have only one game folder working properly.
I don't work for EA
@kreatora Thank you for your help. With you guidance i was able to get some saved sims back from copying an old tray/save file over, but other than that I'm still missing a lot of my library.
@raemariek
Are you sure that those sims you cannot see were not saved as CC? You do not need to have CC to get such an effect. Just sometimes have some mod in the game is enough. Try enabling the "show modified objects" option in the library.
Community Manager
