Whenever I try to load Veronaville, it remains stuck at the loading screen. Other neighborhoods and the clean version of Veronaville works perfectly. I have had the issue before with certain mods and cc, but now it suddenly stopped working at all. I have had another issue, only in this neighborhood, every time when I would place a lot from the lot catalog it was empty.

Did you do anything to this neighbourhood before it happened? Anything, regardless of how small it was.
Do you play the game on Mac?
When you try to open the neighbourhood, for how long does it get stuck for (For how much time do you wait?)

I don't remember doing anything before happening
No
It never finishes loading

Something happened to one file or more in the neighbourhood and the game can't load it.
Have you tried HoodChecker, just to see if it will spot something wrong?
(Also, for how long do you wait for it to eventually load? I know you told me it doesn't load at all, but do you wait for example 15 minutes before giving up? Or more?)

I checked the hood with HoodChecker and I attached below the result
I let the neighborhood load half an hour, and it still didn't finish loading

Looks like almost all of the character files have been deleted.

Yikes. Time to restore a backup.

Yup, the neighborhood is corrupted.
Did the game crash while something in the neighborhood was loading or being saved? That could've borked it, but I'm not sure.

When I saved the game last time, it finished quicker than usual.

For future reference (you do need to restore from a backup), it's best not to use 'save and quit', because sometimes it doesn't save properly. Always use 'save' and then quit.

Just putting this information out here:
@CreamAwe you mentioned the clean Veronaville loads. The 3 BG premade neighborhoods are corrupted. When a neighborhood is corrupted, you do spot some random bugs in it, and it could also just eventually stop loading entirely. I think this is what happened with your original Veronaville (Correct me if I'm wrong), and this is a reminder for everyone to remember to keep backups of neighborhoods!
(I mentioned that crashing in the middle of saving could have borked it, however I don't think that could've been the case anymore since that would've resulted in your neighborhood not showing up at all in the menu screen: Generally, the neighborhood gets saved when you go to CAS and after you make a family in it, when the game is loading a lot and when you quit the game. If the game crashes at these times while it's saving, there's a very, very good chance it corrupts your neighborhood.package file, so the game doesn't recognize it as valid and doesn't show it in the menu screen. Since yours does show, but doesn't load, there's a good chance that what I said about the neighborhood being corrupted from the start is true.)

The original neighborhood have some wrong memories and genetics and family ties, they don't have some kind of malignant cancer that causes all of the character files to delete themselves, lmao.

Yeah, I was wrong
I can't really think of anything else that could've led to the neighborhood completely break, this is weird.