Unknown Error Occurred...what is this?

I have the same problem... What do I do?

@jamiehood @linn This happened to me when I downloaded TS3 onto my 2017 macbook a couple of months ago. It's fixable, provided your graphics cards are recognized—check out this link for more details. I didn't need this fix myself, as my card runs the game fine, but BluebellFlora's advice is always fantastic. The macbook air might not be the best option to play on, though, as the airs don't have the same firepower as pros, much less imacs.

For the Unknown Error itself, there are two possible causes. The first is simple: the alias for the most recent pack you installed (just the icon you click on to launch the game) hasn't been created, so the game can't find it when you try to launch. This process is an easy fix. The second cause is that when you've installed certain EPs and SPs (Ambitions and Late Night in particular), the files from those packs don't get copied to the folder for your newest pack (again, the one that launches the game), so the game can't find those files and won't run. This is the process to copy the files to their appropriate destination; the embedded video is very helpful. You might have to repeat the second workaround every time you install a pack that's newer in terms of release date than any others you have, so it might be worh it to install a few of them at once.

I should add that I'm not great with computers; I just know how to follow instructions, and these workarounds were remarkably easy for me to use. BluebellFlora's website is wonderful and covers pretty much every problem you could ever face on a mac. If you're still having issues, ask on this thread for igazor, who really knows what he's doing and will help walk you through any troubleshooting you might need. It's also a good idea to post your computer's specs when looking for help, as which fixes would work best for you can depend on what you're running.

There are certain combinations of processors and graphics chips (not the ones with AMD Radeons) that put up a barrier to getting TS3 for Mac to work at all. I can't explain that any better than Bluebellflora has done on thousands of message board posts here on this forum board, including the stickied ones near the top, and in a more organized fashion perhaps, on her own blog. Some players can get right through these barriers with little effort, others have to try around a dozen different things, yet others will never succeed. We don't know why except to just say that their hardware combo is not supported.

I don't know which thread the OP was reading, maybe someone else was indeed misinformed along the way and hopefully has been corrected. But the issues are real on many hardware combo sets, sorry.

On the Macbook Air mentioned, personally I wouldn't spend too much time trying to work through that. Yes, one or two of the more recent Airs are just strong enough to run the base game and maybe an EP or two unlike their predecessors that were literally non-starters, but it's just not made for tasks like this and you will have to face the constant threat of overworking and damaging the device if you can even get the game working on it.

@puzzlezaddict So I shouldn't try on either computer? It's a little sad. My air heats up a lot when I play it, but never overheats and shuts down. The game just becomes sketchy and glitchy from time to time. I basically installed all my packs at once, so I'll try to look for those. Thanks for that help. I just hope I can play.

@jamiehood I would definitely not try to play on the air, but the imac might be fine, depending on exactly what it's running. If you post its specs, igazor can give you a better idea of what to expect. I was just saying that if you specifically wanted to play with the Seasons or Pets EPs, and probably IP or ITF, you wouldn't be able to have a good experience on any kind of mac.

The relevant point here is that it is possible to play TS3 on the mac OS side, as long as you're not demanding too much from the game. If you only run a few packs, like I currently do, your experience might be very good. The Unknown Errors are entirely fixable with only a little bit of effort if you follow BluebellFlora's instructions here and/or here (same links as above). Just to be clear, there are two separate issues that cause an error message, but both can be addressed fairly easily.

Most people would suggest installing the base game first, making sure it runs, and then installing packs one at a time until you get the hang of fixing the errors, but you can try to fix them without uninstalling first if you want. If you do uninstall, there's a process to uninstall a single EP or SP, and another to uninstall and reinstall the entire game. Otherwise, you can have all kinds of issues with leftover files that don't get cleaned up. These instructions are easy to follow as well.

If you can Bootcamp the imac, you can run TS3 on the Windows side exactly as if you had a PC. This is probably doable from a system standpoint if the computer is new, although again, igazor is the expert on this issue. The only other questions are whether you have the drive space for a Bootcamp setup and whether you're willing to do it.

@puzzlezaddict Ok, I will try to follow the directions

@puzzlezaddict I tried the directions. Apparently in my Sims 3 folder in Applications, there should be an uninstaller, but there isn't. There's only the readme.text for every pack. Am I looking in the wrong place?

@jamiehood I PM'd you.

Not sure if this has already been mentioned elsewhere but... I was having this problem on my late-2012 iMac and tried the clean uninstall/re-download; nothing worked until I ALSO deleted both the Cider Preferences and The Sims 3 Preferences folders from the library>preferences files.