When I try to launch The Sims 3, I get a dialogue saying, "Unable to start game

@StephJ82  Okay, in all honestly I'm running out of ideas for how to identify the graphics card.  However, it is possible that something else is preventing you from launching your game.  In your position, I'd do a clean uninstall, or rather another one, create a brand new user account on your mac, and try to launch the game in that account.  (And then try the edits there too.)  We've had cases of random stray files causing issues where the only solution was to create the new account; those stray files would be left behind in the old account.

I understand it's more work to uninstall, delete the hidden library files, create the new account, and install the base game again, but if there is in fact some other stray file causing the unknown errors, the game will never work until it's removed from the picture.

https://bluebellflora.com/how-to-do-a-clean-uninstall-and-reinstall-on-a-mac/

And in the meantime, I'll ask for advice from someone who's been doing this for a long time; hopefully, she'll have some insight.

ok thank you for everything

@StephJ82  I think I may know why the .sgr edits didn't work.  (I was messing with the files myself tonight, and I realized something weird was going on.)  If you're willing to try one more time, there's a simple way to address what I believe was the problem all along.  I'm not totally sure, but I'm thinking this might actually work.

If you're not interested in trying again, I totally understand, but I'm here if and when you want to give it a shot.

Hi @puzzlezaddict I’m willing to try if you are.  Thank you 

@StephJ82  Alright, I really hope this makes a difference.

The problem for me, when I was messing with my files last night, was that every time I typed anything out, the quotation marks around where I was typing changed from the correct kind (straight vertical) to the wrong kind (at a slight angle, like the ones we'd use in normal writing).  But this didn't happen if I just copied and pasted a line from somewhere else.  So then the trick is to never actually type out the line you want to add to graphicsrules; just copy it from graphics cards.

So, you can copy over the graphicscards.sgr you downloaded, or download a fresh one from here:

https://bluebellflora.com/2018/07/24/sims-3-mac-players-i-need-your-help/#Filesready

And put copy over your original graphicsrules too, or download a fresh one from the same site, for the Iris Plus Graphics 650.

Instead of typing the proper text into graphicsrules, copy and paste it  from graphicscards.  Once you've copied the text you want to use, you can highlight the word Havendale and then cmd-V to replace it, and the quotes shouldn't change.  If they do—it's hard to see the difference, but it's there—you can just copy a quotation mark from elsewhere in graphicsrules and paste it over the quote mark that changed.  This is still the line you want to alter:

elseif (match("${cardVendor}", "Intel"))
seti intelShadowColorFix true
if (match("${cardName}", "*Havendale*"))
seti cardLevel $cardLevelMedium

where you replace Havendale with Iris Graphics 540.  If that doesn't work, you can once again try putting Iris 540 in both graphicscards and graphicsrules instead.  But instead of just deleting the word Graphics like you would normally, highlight it and then press delete; this should prevent the quote marks from changing.  And once again, if they do, just copy and paste the proper vertical quote marks from elsewhere.

hey @puzzlezaddict I tried to follow the stuff but I am getting really confused now sorry

@StephJ82  It's fine, don't worry about it.  I think it might be easier if I just sent you the text you needed, so you could copy it into your graphicsrules.sgr file without needing to worry about the punctuation marks or anything.  I've uploaded the text, and I'll PM you the link.