NPCs and Homeless constantly spawn from Apartment lot.

[Menaceman]

How do I stop it?

I recently downloaded an apartment lot from MTS. I added it to my game and made a few alterations to it. All of the doors to blacked out apartments are marked as NPC doors and the rooms have hidden room markers in them. All public rooms have public room markers in them. There is a set of lifts that goes to every floor and spiral stairs that run along side them.

The first minor issue is that my Sim will NOT use the lifts even when clicked on directly. He will always use the stairs. The only way to get him to use the lift is to remove one of the stair sets making the lift the only option. There appear to be no routing issues with the lifts when he does use them.

The main issue I have is that NPC Sims and those belonging to the Homeless household spawn constantly at the lift! They arrive at the lot, head straight for the lift and then fade out in front of it. Some time later in the middle of the night I get notifications that "it is late" and then there is a mass exodus of between five to ten Sims all leaving the lot from the lift only to return later on. In some cases I never actually see them come back but when it gets around to night again there is another load of messages and the Sims leave again. This happens EVERY night.
I have seen mixologists, bouncers, a paper boy, burglar, firefighter and Sims belonging to the Homeless household all visit the lift.

There are Sims genuinely living in the other apartment rooms on the lot but if I use the call box it is populated with well over 30 Sims and there are only 7 rooms besides the one belonging to my Sim.

Is there something I need to do to the lot (besides killing it in a fire) that will enable it to function correctly and remove the surplus Sims from thinking it is home?

I had this happen to a previously custom built apartment lot before but I think that was due to forgetting to set NPC doors. When I did that the surplus Sims went away only the doors are already correct this time.

[Painkiller]

Are there public room markers in the lifts?

[Menaceman]

There were but I took them out as I thought that was causing the lift issue. He still didn't use the lifts even with public room markers. Or do I need them in to prevent the NPC issue?

[Painkiller]

Apparently it's what forces the NPCs to use the lift instead of fading in front of it.

http://www.modthesims.info/showthread.php?p=3436936#post3436936

the elevator shafts should have a public room marker in them too, so that the NPCs can enter the elevators.

http://www.flyingacres.com/NeighborlySims3/showthread.php?tid=1904&page=1

the only two PUBLIC Room markers are IN the elevator shaft (place that one BEFORE you place the elevator), and out in the elevator foyer. Those two, on ANY floor where you want your Sim to be able to get out of the elevator, MUST always be PUBLIC.

I know these are in no way 'serious references' but the problem is that there aren't many apartment building FAQs out there anyway.

[Menaceman]

Well I just took my game back to before my Sim moved in and tried again after making sure the lift shafts had public markers in them.
As soon as my Sim arrives at the lot to head to his room three NPC Sims immediately leave the lift and walk off-lot. They are usually mixologists or bouncers. Within the hour I had a firefighter turn up and fade out in front of the lift.
I haven't played long enough on this run yet to see but last time whenever a paper was due to be delivered the paper boy would cycle to the lot as usual, drop the paper and then head to the lift to fade out instead of cycling away.

I'm going to remove the lifts and see what happens.

ETA: Without the lifts there don't seem to be as many NPCs spawning but it still happens only now they are vanishing and spawning at the edge of the lot instead of by the lift (which I have removed as mentioned previously).
I just counted and 51 Sims are listed on the callbox of this 8 apartment building!

ETA2: Moved my Sim into another apartment lot based from the same downloaded lot and there are no issues. My Sim still doesn't like using the lifts but will do on his own when the carpool arrives. No random NPCs spawning or vanishing and one genuine NPC family has moved in.
When telling my Sim to visit the old lot there are still 25 Sims listed on the call box despite there being no available 'Ring Bell' options on the NPC doors. They are all greyed out.

ETA3: It's not the lot! I removed the lot completely and all of the NPCs listed as occupants all started to appear on the call box of a different apartment lot which was previously listed as having no inhabitants. Looks like this world save is just doomed to never have apartments. It did it with a prebuilt EA shell apartment as well.
I've played an EA apartment in Bridgeport but never noticed this behaviour before.

ETA4: I took drastic (?) measures and made use of the "destroyallhumans" command. Putting a fresh copy of my Sim into the apartment lot I have not had NPCs insessantly spawning and leaving the lot. I have seen ones such as burglars and firefighters show up who I don't think should be doing but none are spawning out of the lift in a morning or complaining it is late before leaving.
There are only about 15 Sims listed on the call box now and roughly 25 on the neighbouring apartment call box. Still doesn't seem right but the spawning at least seems to have stopped... for now.