I'm still having some issues, getting error 12 in my world. Should I just do a factory reset and start over with a new family?

Maybe, but if you are still using 7 or more of your 8 GB of RAM, then you will likely end up in the same place soon enough. Do your Task and Resource Managers now show more than nearly zero RAM available to work with while the game is running? And we kind of glossed over this, but you said you had 16 GB although your computer thinks you have half that. No one "needs" 16 GB to run TS3 (without the overhead of all those other processes) but I would be trying to find out why this is happening and where the rest of your RAM went/why it's not being recognized and used unless you were mistaken about the 16 GB spec. There could be a mechanical problem or perhaps one of your RAM chips is not really in its slot all the way as it should be. Or if a RAM upgrade was performed, perhaps the wrong kind was added in and it's not compatible with your system or what was already there.

Please forgive me for my ignorance when it comes to RAM and computer stuff. I really need to get better at this. Anyway, here is where I got 16GB.
https://gyazo.com/b3aaa1dff21d40d19bab16369af8dbb9

But I think that's wrong, because RAM info says this:
https://gyazo.com/1375cf3f676b0525ca9ee36700b30642

So that was an error on my part and I apologize for that.

I'm also not sure if this helps, but here's what it says in Task Manager while the Sims is running in a world:
https://gyazo.com/4433f7376b037b8ad280051dd8c40c36

Also, I think I figured out what was causing error 12: (I think) Discord was running when I was saving the sims and got error 12, but when I ran the sims again w/o discord running, it saved just fine. But that didn't last for long.

Now it's just turning into circles - TS3 crashing when traveling to another world, and then when deleting travel db and having it work and traveling to the world, it gets into error 12 again. I'm really sorry for all the issues this is causing. Not really sure what to do.

That tiny slice of your Task Manager shows that Google Chrome is running 18 independent processes at the time you are playing. Can't see what else might be running. I know that modern browsers tend to get carried away with predicting what you are going to do next and can actually take over the entire system, but that seems extreme. Might you have had something like 18 browser tabs open and running at that point?

With 8 GB of RAM you should be able to run a web browser while the game is paused, or pause a web browser (sort of, I mean stop interacting with it) while the game is being played. But we're trying to troubleshoot resource allocation here, running other programs and unnecessary processes like Chrome and Discord (already tended to) are just going to confuse everything. When I had 8 GB, often enough I still had to close out my browsers completely when I was ready to return to gameplay to stop them from taking over.

Travel transitions are delicate even with NRaas Traveler in play. If you watch the Task Manager while one is taking place, you will see that they cause RAM usage to spike way up at least twice, while the world being traveled from is offloaded and when the destination begins loading up. If any of those spikes go into the 3.5 GB danger zone (or maybe lower even), then the game will be unstable and may well crash or Error12 even if there is some RAM available left for the game to use. In that case, if you aren't already doing this, try to relieve as much stress on the game as possible before beginning the travel sequence. Do not be online/signed in within the game, no TS3 store shopping experience, turn all of the graphics settings in Game Options down to their bare ugly minimum and switch off Advanced Rendering, and only attempt travel after a fresh reload with a Save As upon successful arrival. The game will look terrible that way, but you can put the Game Options back and reload after the safe arrival if you can manage one.

Sorry if this sounds harsh at all, but if you are unable to run the game without all these other programs using up system resources then you either need stronger components (like more RAM) or probably more realistically you need to avoid world travel in-game.

Understood. So, basically, the main issue is that I don't have enough RAM to travel in game?

The modern versions of Firefox do this too now. I got disgusted with how heavy handed it was being and switched to the Waterfox variant, but it still happens sometimes (not nearly as bad/often). These web browser developers seem to be under the impression that we are running web browsing machines and shouldn't have an interest in using our computers, whether big and fancy or minimalist and really better suited for light tasks, for anything else at all other than running their precious program.

Web browers are driving me nuts! I switched to Chrome a few years back because some sites I used regularly weren't liking Firefox. Then I got tired of Chrome's bloating and switched back to Firefox...which also bloated. Right now, I'm using Opera, and although it tends to run a bit faster than Chrome or Firefox, it's not much better in terms of bloat. What is this "Waterfox" thing? ....But then, if it's not much better, I guess it's not worth it.

Wonder if Netscape's still around. Why is there not a browser that DOESN'T assume that you've got, like, 32GB of RAM to play with. :p

....OK, OK, I'll stop ranting.

What the browsers seem to do is figure out how much RAM we have total and attempt to use all but 1 MB of that. Or maybe it's all of that plus 1 MB more. So 32 GB vs. 4 GB installed doesn't matter.

Since Firefox is open sourced, there are variants around that run on the older pre-quantum engine and/or are just less prone to the bloat. I use Waterfox because it still supports RSS which Mozilla incorrectly decided nobody uses anymore and retired it, and as a bonus my favorite extensions that haven't been updated for the new Firefox engine still work. Soon Mozilla will figure out that almost no one uses their browser to navigate the web anymore either and will terminate the web services portion of the browser in favor of more features like emojis that no one really cares about, but we do have to be grateful for the innovations they have provided along the way.

Waterfox: https://www.waterfox.net
Pale Moon, another popular Firefox variant: https://www.palemoon.org

Netscape became Firefox sort of, before it was branched off to AOL and then dumped long ago. So in a way we are already using it but not the classic army tank of the web Navigator/Communicator that so many of us loved in a prior decade.

Not sure any of this helps the OP, as what we are trying to do is entice them to not have any browsers up and running while stress testing their game and negotiating travel transitions.

Yes, yes, we're leading people astray, aren't we? It's my specialty. Thanks for the links, and the explanation, though! I do miss NetScape... *sigh* But then, I have powerful nostalgia for small, non-obtrusive OSs like Win98, too.

OP, close your RAM-eating browsers, man. I know it's fun to be able to do stuff on the internet while you play or while the game is loading or saving or whatever, but...something's gotta give, man. Either you need more RAM, or you gotta streamline what you're doing when you're playing.

Of course, I'm totally being a hypocrite, because I have the same amount of RAM on this machine as the OP does, and *I* run a browser while I play. But not much else, and I keep the tabs to a minimum, especially if I'm going to do something intense like saving the game or traveling to a different world.

Okay, I'll try to run the sims w/o any browser in the background and see if that helps.

Edit: Running it w/o anything in the background still comes up with an error 12 in a different world, but not my home world. Is there anything else I can do? Should I buy more RAM? I'm really sorry for causing so many issues.

Hmmmm...Have you run the Save Cleaner on your save at all? (The link is to a download of an older version of it, which ironically is the one that works with 1.67/1.69. Here is the download page for the newest version. That doesn't work with the newest patch, but it has info about what it does and such. With the older version, you just need to extract everything to a folder on, say, your desktop and click the EXE in it. There's no installation.) Anyway, I'm not sure if that helps with Error 12s, but it does decrease the file size of saves.

Other than that, I think that between nitromon and igazor, pretty much everything's been said. You may need to start a new save or just resign yourself to not traveling. More RAM likely won't help with the situation because the game can only use 4GB, max. More RAM would simply let you do other things on your computer -- like running a web browser -- without eating into that 4GB that the game can use.

I think the cleaner might have worked! I didn't have Discord open, but I think the cleaner did work when it comes to error 12. Just now it's crashing. LOL