Installing .package files on Macs (the new way)
We all know that the new patch is messing with our .sims3packs. However, there is an alternative. It is called 'Mods' or 'packages'. These mods can also add features or tweak stuff. You can get these by installing the 'framework'.
There have been several guides to do this before. But the Ambitions EP updated the way to make the framework, so the posts are outdated. The new version even comes with some support by EA. Even better, no transgaming or Bin folders to mess with!
First: Find Your Mods (Folder)
First, go to Documents/Electronic Arts/The Sims 3. create a folder called 'Mods'. Inside create a folder called 'Packages'.

Second: Get Your Resource(.cfg)
Second, get the *NEW* resource.cfg file (secondary click and download linked file: (It won't be nice if you get the old one.)
Open it in TextEdit and make sure the first number is 501, NOT 500.

If appeared resource.cfg.txt, rename it in finder by secondary-clicking on it and then clicking 'Get Info'. Then go to Name & Extension, take off the .txt part, press enter and click 'use .cfg'.

Place it in Documents/Electronic Arts/The Sims 3/Mods

Now install some CC.
Suggested sites:
Third: Where do I put the Files?
Place the .package files in Documents/Electronic Arts/The Sims 3/Mods/Packages.

Fourth: What Now?
Open up your game, if you downloaded a mod (something that tweaks the game, e.g. faster nectar making) it will pop up when you start the game. If it is an object, it will have a folder in the right-bottom corner in Buy Mode. This never happened in older versions of the framework.

Well, that's all folks!
Comments
(I had ambitions, played a while then decided that trampolines weren't worth laundry-- and the game felt slower to me, so I uninstalled it.)
I have the base game and HELS installed. My resource file is 500 and it's in the following folder.
Show contents: Contents/Resources/transgaming/c-drive/program files/Electronic Arts/Sims 3
A folder earlier than the new method.
When I replaced my 500 in the same location with 501, the CC did not show up.
When I deleted the 500 file and put the 501 file in the mods folder, the CC dids not show up.
I also tried both. The 500 file in the Sims 3 folder and the 501 file in the Mods folder (so that when I install the next exapansion, it would be in place.). The game would not open at all.
So for now, I am ok with the 500 folder in the Sims 3 folder.....I will just freak out when the next expansion comes
I only have base game and HELS installed, but my patches are up to date.
in Sims 3/Game/Bin?
I deleted that file and put the resource 501 in the new place... no CC.
Sorry
I put it back the way it was.... it's working ok. I bookmarked your instructions and if I install an expansion of a new patch (my launcher says up to date, after refresh) I'll try it again.
I don't know why, but the old method is working and this isn't....for me. I'm not suggesting it doesn't for other people.