How to Install Software from DMG Files on a Mac

One of the most common mistakes I see among new Mac users is fumbling with how to install new software. The process for installing new applications on your Mac can be confusing at first because it differs greatly from Windows’ software installation process. Nevertheless, the Mac method of software installation is actually quite simple and intuitive once you are accustomed to it. If your desktop is littered with DMG files and white drive-looking icons, read on!

Software installation with Mac OS X is very different different than the Windows world. On a Windows PC, you run an installer, tick off a few check boxes, and wait for the progress meter to reach completion. On a Mac, you simply drag and drop an Application into your computer’s “Applications” directory. The trick is that most Mac applications are distributed in DMG files, and many new Mac users end up running applications out of those DMG files instead of copying the applications to their Mac’s “Applications” directory.

Enough explanation, here’s how to install most Mac OS X applications:

1. Download the app’s .DMG file. Often times it will end up on your desktop.
2. Double-click the .DMG file to open it up. Another new icon with a name similar to the .DMG file will appear on your desktop.
3. If a new Finder window doesn’t automatically appear, double click on the new icon that has appeared on your desktop. Guess what? A Finder window will appear.
4. Locate your application’s icon within this new Finder window. Drag and drop it into your “Applications” directory.

Further Explanation

Alright, that was the abridged version. Here’s the long-winded version. I have just downloaded the DeskLickr application, and DeskLickr_1.2.dmg is sitting on my desktop. I double-click on DeskLickr1.2.dmg and a new icon labeled “DeskLickr 1.2″ appears on my desktop. Here’s what my desktop looks like at this point:

Fig. 1 - A DMG disk image mounted and ready.

Since most DMG images also pop up a new Finder window when they’re ready for use, the following window has also appear on my desktop:

Fig. 2 - The Finder window that appears after I double-click on the .DMG file.

Different applications are going to show you slightly different Finder windows. Each application’s designers like to add their own artwork. Glitter aside, most applications are also trying to tell you the same thing. See the arrow pointing from the DeskLickr icon to the Applications folder? That arrow is telling me to drag the DeskLickr icon and drop it into the Applications folder. Once I’ve done so my application, in this case DeskLickr, is installed.

If an application does not provide a shortcut to the Applications folder in which to drop the application icon, you’ll need to pop open a new Finder window. Press CMD+N to open a new window, then drag the application icon over to the “Applications” folder in the left-hand sidebar of the new window. Here is an illustration:

Fig. 3 - Dragging the application into the “Applications” folder of a new Finder window.

House Cleaning

Once your new application is installed, it’s time to do some house cleaning. You no longer need the disk image you downloaded, so perform the following tasks:

1. Close any Finder windows that have been left open.
2. Eject the disk image (not the .dmg file). Click on it’s desktop icon, then press CMD+E.
3. Delete the .dmg file by dragging it to the trash.

That’s it! Your new Mac application is installed and ready for use. But wait…

Bonus Tip: Add Your New Application to the Dock

I knew you were going to ask, so I figured I would cut you off at the pass. In order to add your new application to the Dock, follow these steps:

1. Open up a new Finder window.
2. Click on Applications.
3. Locate your application’s icon.
4. Drag the icon to your Dock, and drop it wherever you like.