I downloaded "essential" mods like SmoothPatch and NRaas Mods. I did disabled EA story progression and used Nraas' version, but never works! I tried reading these forums I saw when I was searching:

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I tried but it never did or is it just me who is really bad at reading comprehension !

Check settings for Nraas SP, that emmigration is off.

Does that bring back all of the families once I did that or do I have to start a new game for that to work?

This is my mods folder just to check if there's something corrupted, conflicted, or wrongly placed to overrides or packages. I checked every mods I downloaded, they seem fine to me.

here

As far as I know, it does not bring them back. You would have to start a new game, or load from a save, from before they went MIA. As for what is in your MODs folder, best thing to do is grab dashboard tool... https://modthesims.info/d/387006/si...8217-25892.html

You seem to have a Mods folder in the Mods folder.
The Sims 3 > Mods > Packages > Mods

That might confuse your game. Try to rename that last Mods folder.

And yes, if EA Story Progression is still active and deleted your townies, they're gone.

Did you check for conflicts with Dashboard?

Isn't that for CCs?

Yes, I did. All it found is a conflict of two gardening mods and duplicated muscleslider fix.

I did, but I wanted to add all of the families back in Sunset Valley instead of populating random-generated sims. Is there any possible ways to do it?

this is the scripterror:
<NRaas.ErrorTrap>
<ModVersion value="100"/>
<BuildVersion value="0.2.0.209"/>
<Installed value="BaseGame, EP1, SP1, EP2, SP2, EP3, SP3, EP4, SP4, EP5, SP5, EP6, SP7, EP7, EP8, SP8, EP9, EP10, SP9, EP11"/>
<Enumerator value="1"/>
<Content> -- Correction Logs -- Destroyed Object Found: Sims3.Gameplay.Objects.Door.DoorSingleStenciledGlassMission Destroyed Object Found: Sims3.Gameplay.Objects.Door.DoorFrenchTwoTile Destroyed Object Found: Sims3.Gameplay.Objects.Door.DoorSlidingPatio SimDescription Removed: Madison VanWatson SimDescription Removed: Lucas Flores SimDescription Removed: Elena Flores SimDescription Removed: Antonio Flores SimDescription Removed: Enola Curious SimDescription Removed: Kepler Curious SimDescription Removed: Margarita Flores SimDescription Removed: Eliza Cranky SimDescription Removed: Tori Kimura Loaded Assemblies: ArsilCustomBeverages ArsilRestorationSpellFix Arsil_DoHomeworkWith BuzzlerScribblingPadEdit Fantuanss12.Harverster_TempFix FullMoon Gamefreak130.NoMagicClothesline Gamefreak130.SmartphoneDating Gamefreak130.TrulyEclipsingFog Gamefreak130.WeatherForecastTweaks Knight.AnnoyancesDisabler LazyDuchess.BuyBuildSearch LazyDuchess.NoSocialGroups LazyDuchess.PuddingFaceFix LazyDuchess.SmoothPatch LazyDuchess.SmoothPatch_MasterController LibraryAddDoors NRaasDebugEnabler: Version 54 NRaasErrorTrap: Version 100 NRaasGoHere: Version 44 NRaasHybrid: Version 10 NRaasMasterController: Version 134 NRaasMasterControllerIntegration: Version 134 NRaasMover: Version 28 NRaasNoCD NRaasOnceRead: Version 13 NRaasOverwatch: Version 122 NRaasPorter: Version 42 NRaasRegister: Version 81 NRaasRetuner: Version 10 NRaasSaver: Version 21 NRaasStoryProgression: Version 267 NRaasTraffic: Version 21 NRaasTraveler: Version 87 NRaasWoohooer: Version 129 Nandonalt.SupernaturalBabies PhoebeJaySims.CourtV2_b_ PrankCalls Savanita.HandBabyTo Savanita.PickUpToddlerFix Savanita_BabyInteractions Savanita_ToddlerInteractions ScriptCore SeasonsSymptoms SimIFace Sims3GameplayObjects Sims3GameplaySystems Sims3Metadata Sims3StoreObjects Skydome_EveryoneCanCarryChild SleepSofa SleepyGenius.Mod.TaxiCharge StudentUnionAddDoor StudentUnionBuffetTable StudentUnionLibrary System System.Xml Twinsimming_Dirty_Laundry_Mod Twinsimming_Phases_Mod Twinsimming_Spray_Tan_Mod Twinsimming_Sunscreen_Mod_V3 Twinsimming_Take_Selfie_Mod Twinsimming_Tooth_Fairy_Mod UI granthesOMSP icarusallsorts.BandInteractions icarusallsorts.MicrowaveFood icarusallsorts.NectarGlassReplacer icarusallsorts.PoolLifeguard icarusallsorts.Scolding mscorlib simbouquet.GetToKnowFix simbouquet.MoreGreetings </Content>
</NRaas.ErrorTrap>

As far as I know, they are gone. If they are still in your aquaintances, you can invite foreign visitor, and then place them using Nraas MC, but I don't think they show there. Only way is to start a new save series, or load a save from before they left.

Sorry if I asked many times, but will the settings I configured saves every time I start a new game?

Still didn't work though. When I took off my mods from the folder, all pre-made families appears when I started a new save, but when with mods, they disappeared. I checked Delphy's Dashboard, and only detected 2 duplicates and 1 conflict mods from gardening-related mods.

I'll also try to solve this issue to Reddit.

Better upload Error Trap files over at NRAAS. They can tell you what this all means.
Since removing your mod folder solves the issue, have you renamed it?

Wait, somebody told me that a mod conflicts the sims 3, if it solves the issue, I don't need to send this to NRaas

*on reddit

I'll close this thread, the issue is now solved on Reddit by someone. Apparently, the cause of the problem was the science professor fix, and I read the instructions wrong.