Unplayed households gone

If you have a lot of households overall, eventually the game will cull some from the game for performance reasons. (I'm assuming you play with Neighborhood Stories's deaths turned off and with aging off.)

Sounds like general population culling, then. You can protect households by clicking on them in Manage Households to make them be in My Households.

Load up your save file, go into Game Options > Gameplay > Maximum Sim Count : Unlimited
This should prevent culling altogether. Normally when it's set to a limit (80, 150, 200 Max Rec), it starts culling once it has reached that limit.
:warning: The downside to Unlimited is that it can and will tank game performance. You may want to follow luthienrising instructions instead.

"Kellogg_J_Kellogg;c-18324172" wrote:
I've made a note of which households were deleted...all created by me as potential partners for my played sims and as they've never appeared randomly in the game they were purged by the system. Every unplayed sim still there are either NPC service careers or have been met as random townies.

The game will prioritize Sims that have relationships of any kind with Sims you've played.

Yes, ageing and neighborhood stories are off.

I've made a note of which households were deleted...all created by me as potential partners for my played sims and as they've never appeared randomly in the game they were purged by the system. Every unplayed sim still there are either NPC service careers or have been met as random townies.