Again let me post what I just previously posted 3 post's ago. Let me clarify again as well, if you downloaded the digital download version of the Sims 3 (PC WINDOWS) edition/version and are trying to install it on your (MAC OSX) then your not out of luck. Although initially when you try to install it, it gives you a "Cannot verify the integrity of the installer" error message and closes. There is indeed a fix for this, so that you can install it on the (MAC OSX). If you follow these step by step instructions you will have it running on your MAC in no time.
Pasted from a previous user,
I'll take you through it step by step. Do exactly as I do.
1. Unpack the zip file that was downloaded from D2D or in this case digitalriver. A folder should show up. This would be the folder with the installation files.
2. Open "Disk Utility" on you mac.
3. When Disk Utility opens, click on the "+new image" tab. When the drop down menu appears, start with the top dialog box. Name it "Sims 3." 2nd box- save it to the desktop. "Disk Name", don't touch that one. The next box "volume size", hit that, and select custom. When the next window appears, Click the left box and put in "6". In the right box, change to GB. Now click on the Partions Tab, change it to just plan old CD/DVD. Don't touch anything else, click create.
4. Close disk utility.
5. Go to the desk top. There will be a Sims 3.dmg file, and a "Disk Image" Icon. Go INTO the folder that was extracted from the sims 3 zip file. Highlight all contents in the folder, drag them onto the "Disk Image" Icon. It will copy them. DO NOT DRAG THE FOLDER ONTO IT. GO INTO THE FOLDER, AND GET THE CONTENTS, DRAG THEM OUT OF IT.
6. When it's done copying, double click the "Disk Image" Icon that we created, go inside, Click the "The Sims 3 Installer" Icon. It will run.
Enjoy.