Steam – Choose install location Steam games on Mac

Most multi-platform games share a large amount of data between platforms, even though the actual executable is different.

Let's look at Half-Life 2 and other Source games. They have lots of *.gcf files inside the Steam\steamapps folder. Those files contain all the multimedia assets (levels, audio, textures, 3D models...), and such data is identical to both Mac and Win versions. Thus, you can safely copy such files from your Mac Steam to your Windows Steam, saving you a few gigabytes of downloads. Then, the Windows Steam will still download Windows-only files, but they are quite small, maybe less then 100MB.

It also works the other way around: copying files from Windows to Mac.

What I've described should also work on most steamplay titles, that are available on Steam for Mac and Windows. (but you might need to copy files from subdirectories inside Steam\steamapps\common)

However, if you want to download a Windows-only game, then you might need to run the Windows version of Steam. You may achieve that using one of the many virtualization options (VMware, VirtualBox, Parallels), or even try your luck running Steam under Wine (but that might be too buggy).

When you install a game, Steam places it in ~/Library/Application Support/Steam/SteamApps/ and creates an alias in ~/Applications/ which you can use to launch the game. It does this because different games may have different directory structures—unfortunately, not all Mac games come in neatly-packaged app bundles. Because of this, it's not really possible (or a good idea) to trick Steam into putting the game data in /Applications/ instead.

It's safe to exclude ~/Library/Application Support/Steam/SteamApps/ from your backups since no user data is kept there, only the game installs. Save files are kept elsewhere in your home directory, depending on the game.

If you really want to keep game data out of your home directory, you can make a symbolic link at ~/Library/Application Support/SteamApps/ pointing to somewhere else on your disk, perhaps in /Users/Shared/. Here's how you do this:

1. Shut down Steam.
2. Move the ~/Library/Application Support/Steam/SteamApps/ folder to wherever you want it to be.
3. Open up Terminal and change to the Steam folder by typing:
   cd ~/Library/Application\ Support/Steam
4. Create a symbolic link in this folder pointing to the place you moved the SteamApps folder to:
   ln -s /Users/Shared/Steam/ SteamApps