If you are running the Disc version, check out    It is highly advisable that you purchase the Steam version of SimCity 4, as it has far fewer issues than the App Store version.  For one the Steam version isn't sandboxed, so plug-ins are easy to install, and you can utilize the terrain/mapping files for your regions.   Download NAM from LEX Download   If you are running the Steam Version, there is no need to move any files to make the plugins work, they just will.  For the App Store version, you will need to move the contents of the newly created Plugins Folder to "~/Library/Containers/com.aspyr.simcity4.appstore/Data/Documents/SimCity 4/Plugins" (use Command + Shift + G to easily navigate to the folder).   There are no special setups, no tweaks to perform, no modifications needed to get either Digital version to run.  However, the Aspyr port seems to have a limit as to the number of files you can have in the plugins.  No one knows for sure, except that the Steam version has a higher value than the App Store version, and both are significantly reduced when your system isn't connected to the Internet.