I've come across this issue a few times in my game. I am currently trying to lower my population, however, ghosts don't age or die so I would like to make some human to help with the ghost population. I tried feeding the townie ghosts ambrosia, 1 turned human 2 others did not. I noticed the 2 that did not didn't have a tombstone in their inventory. I then did some research to see if there was anything else that would change them. I found the cure elixer so I tried that on 3 townie ghosts. Nothing. Again, noticed they did not have a tombstone in their inventory. I then looked into their family tree, all the ghosts that didn't have a tombstone was born a ghost. Is there any way to get their tombstone that is apparently missing? Is there any kind of cheat to change them? Also you can't change ghosts who were born a ghost through CAS, that option comes up with what ever occult they are. Like some I have are ghost fairies. Those come up in CAS as fairies not ghosts. Thank you in advance for any ideas to try

Ghosts without a tombstone are basically broken Sims that produce error after error. There is an option in the Overwatch mod called "Find Grave" which can try to create a tombstone for those ghosts that are missing theirs, but it's going to be a hit-or-miss operation in your case. You could also try to kill them with MasterController's Force Kill command, as this should remove them temporarily from the game and produce a tombstone in the Mausoleum. And if this doesn't work either the only other suggestion I have is the radical step to remove them completely from your game, preferably with MasterController's Total Annihilation command.
Ghosts without a tombstone are something that shouldn't be.

(BTW, unless you use a mod that prevents this, ghosts should age normally, like any other Sim)

Nope no mods that change the ghosts. They have never aged normally. They go through the baby, toddler, child and teen stage just fine but once they hit young adult just like a vampire they stop aging. I tried the mastercontrollers find grave option and that only showed sims that were completely dead and in the mausoleum. Does the overwatch mod have a different find grave? I can look into it I have that mod as well. Also if I were to force kill them with mastercontroller, what does that do with their current relationships and jobs? I just want a few of them to age so I don't get over populated with ghosts. I don't mind a few of them to stay. Kinda like having some that my sim has known since I first started playing. I have one mod that lets all the other occults except vampire to age like normal sims to also help on population. Just gotta figure out the ghosts lol I will look into the overwatch option and see what it says for me. Also these ghosts don't produce any errors. Unless they do something that pops up a story I don't hear anything about them. Also if no tombstone means their broke, then I guess ever ghost except for the start of the family try is broke and that is a ton of ghosts. lol

Yeah, sorry, I meant MasterController not Overwatch for the Find Grave option: Find Grave - Locates the grave of a dead sim (and can sometimes respawn a missing gravestone from my experience)
Then there's also: Bury the Dead - Runs through the genealogy of the town and creates urnstones for all ancestors
And: Force Kill - Immediately kills a sim selected from a list. Handy for killing ghosts that lack urnstones

A Sim that has been Force Killed will lose its job but maintain all relationships. If you resurrect it immediately , most things should be intact. Inventory gets destroyed, however.

And with regard to aging: my ghosts age, all of them, and if they wouldn't Overwatch would force them to age again. And vampires that don't age isn't normal either. You do seem to have a mod that messes with the aging manager in an unexpected way.

And yes, a ghost without a gravestone is broken, as you have already noticed when you were unable to bring them back with Ambrosia. The errors might not be written to a file without ErrorTrap or AwesomeMod, but the last case I had I got AwesomeMod Flagrant System Errors every 10 seconds from the moment that ghost had lost its gravestone.

You use a mod that handles inventories, like StoryProgression or Overwatch? That might be why they lost their urnstones.

I do have errortrap, storyprogression and overwatch along with a lot of NRAAS mods lol I went in and tried that force kill. figured I wont save it if I didn't like what had happened. So I tried it and was able to get the gravestone. I experimented with it for a bit. Depending on what family was my active family the resurrection seemed to effect the ghosts differently. I had noticed that if I wasn't in the ghosts family then that ghost even after I resurrected it wasn't going to age. I had gone into that ghosts family after the resurrection and that sim wasn't going to age even though she was human again. So I tried again, this time I was in her family for my active family and she resurrected just fine and was going to age. I then tried another one. This one, however lived alone. I wasn't sure what would happen if I force killed him while in his family since it was just him so I went to my family and then force killed him. When I resurrected him he didn't keep his house, instead he was put with one of his family members. Since I force killed and resurrected him not in his family he didn't have the aging either. So I had to force kill him again while in his family and resurrect him and then he was fine with the aging. I then went to another family. This time I was in their family, force killed the YA offspring of the original ghost from the start and she resurrected just fine with aging. I then went to the original ghost and just clicked on her gravestone and she resurrected just fine as well. Yes they lose their jobs but all of mine kept their inventory. I just went into mastercontroller and fixed their jobs and levels they were at. Glad this worked. I don't mind have the supernaturals just don't want to be over ran by ghosts lol. Thank you for helping with my question you were a big help. I have used these mods for a long time and love them, couldn't play with out them but I don't understand everything in them. This way seems to take a bit but its worth it

oh and if I do have a mod that changes the vamps and ghosts lifespan then I have absolutely no idea on what it is and must of been added over a year ago because they have been that way for as long as I can remember them. If I added it must of been for a different reason and didn't realize it was going to do that to the sims. I don't mind that it did because to me vamps are forever living and a ghost well a ghost is already dead, doesnt make sense for them to die again lol.