The situation requires a bit of a story, please be patient :D
I'm using Mesa Flats as a main neighborhood. Only after I played the main for some time did I realize I had it as a subhood for another neighborhood I started a long time ago. I really hate redundencies and finally settled on a solution to ensure I only had one truly functioning Mesa Flat: Keep the main hood as is, and delete the subhood. Of course, I moved all my Mesa sims into the sim bin after having them give up their owned lots and such. I used the lot detector (volleyball) to make sure the lot was safe to destroy. There is no cemetary in that neighborhood and no graves or urns on any of the lots. I moved all my Mesa sims into another subhood that looked totally different, renamed them, refashioned them and made half of them "downtownies" so that they were essentially not the same as what I had in my (other) Mesa Flat main neighborhood.

Here's the question - I noticed several Mesa sims had relations with deceased sims in their family tree, but I have no idea where these sims are. As I said, there are no graves in that neighborhood. Are those Mesa sims able to corrupt that neighborhood by being moved to new subhood and the old one destroyed?? I want to assume no, that those sims in their family tree somehow never even existed in game, but I don't know enough about programming and creating to know for certain if that is possible.

Moving from one subhood to another in the same neighbourhood would not corrupt them. It would only corrupt if you moved them to a brand new neighbourhood. Also you didnt have to move them all out first as when you delete a subhood it sends them all to the simbin.

Yes, I'm aware that changing subhoods is not a problem. The question concerns dead relatives that don't seem to be anywhere in the game.

Easiest way to check would be to run HoodChecker on your neighborhood. If it gives you a lot of "Sim does not exist" messages, you messed up and deleted tombstones along with the subhood. Keep in mind that any mod that contains NPCs, like a multi PT mod or some animals, will give you this message as well, so if you get some missing characters that you can explain that way, everything's fine.

Thanks for that suggestion! There are a LOT of "incorrect subject instance" notes. What does that mean?
There are also 9 "sim has no character file" warnings, and 11 "sim does not exist...has relationship with self" messages.

Incorrect subject instance and relationship with self are harmless, if you select the Remove option, HoodChecker will remove them for you. They just happen during the normal course of the game. The only non-removable incorrect subject instance I can think of is that bug where if you fulfill a lifetime wish like "Have golden anniversary", the game gives your memory the picture of a plant or whatever else it will think of. It's annoying, but harmless. Cyjon has a fix for it I think.

I'm very much worried about the nine missing character files though. Do you have any mods with NPCs? That would be Multi PT mods, Rebeckah's animals, ridable bikes, etc. Most newer mods that create NPCs are careful to point this out to you, but some older ones might not. Basically, is there any way you can explain those nine missing character files that does not involve any deleted sims?

If you can't your neighborhood has been corrupted and always will be, unless you restore a backup with the subhood still intact. You can still play it, and chances are it'll stay around for quite a while, but it's going to implode at some point.

BTW, is that Mesa Flats you're talking about the one on here https://modthesims.info/d/621995/me...tion-no-cc.html , or another one? Because the description doesn't mention anything about premade deceases sims or graveyards, which is usually something the Hood Building Group would point out.

Yes, that's the Mesa Flats. It's weird that there doesn't seem to be any deceased sims anywhere, but they are in the family trees of the playable sims. Excuse my ignorance, but how is this possible? That's what's really getting to me. I don't know how deceased sims in family trees can not exist at some point, or leave behind graves.

It's possible I have mods with NPCs, I'm just not sure what they would be. I do have some animals, and some carnival rides that the creator explicitly stated creates their own NPCs. However none of these were used in that neighborhood.

Thank you so much for your reply. I'm going to assume all is fine and just start over if the neighborhood implodes

It doesn't matter if you use the mod in your neighborhood, they're there anyway. Just like the Grim Reaper exists even if you don't have any sim die. Is that Echo's carnival set you're talking about? I don't have that one, so I can't say for sure, but that might account for the missing character files.

That other question you had actually reminded me, do you have the nounlinkondelete mod? Because that should actually protect you from corrupting your neighborhood by deleting graves in the first place.

Ovenhole, yes that's the carnival set. You know everything! If that accounts for the missing character files, no big deal then?

I do have the nounlinkondelete mod. Yay!

Thank you for being so helpful. I guess I don't need to worry about corruption. The question still remains - how does one create deceased family members in the family tree without having them truly exist in game or leave any graves behind? Is that a trick of SimPE or other program?
It's just got me confuzzled now!

Yeah that confuses me as well, especially since I downloaded Mesa Flats to check and there are no dead sims in this neighborhood. I was wondering about this, since HoodBuildingGroup is usually very careful with that sort of thing and will only add a minimum of dead sims in the first place. So, yeah, I have no idea where those sims are coming from. Are you sure they're Mesa Flats sims?

I don't know what they are. They're related to the living sims in Mesa Flats and show up in their family tree, but nowhere else.

Who are those deceased sims, how many of them is there, what are their names, could you maybe provide a screen cap of the family trees ?