As any Mac user knows, running Command and Conquer Generals (including Zero Hour) tends to crash on startup on a Mac running OS X. Here’s how to fix it.
Launch “Activity Monitor”, and from the “View” menu, choose “All Processes.”
Then, search for “gamed”. If it shows up here, it’s running and C&C Generals will crash immediately.
To get rid of the “gamed” process, you need to open Terminal and type the following command:
launchctl load -w /System/Library/LaunchAgents/com.apple.gamed.plist
Now, when you launch Generals, you will be prompted with several dialog boxes. It’s important that you do NOT select Game Center. You can play multiplayer on the same network WITHOUT Game Center!
On the first dialog, choose “Cancel”.
On the second dialog, choose “Single Player Only”.