Files in .dmg format are easier for Mac users to download and install than other file formats. This document describes how to convert a file saved on a CD or DVD into a .dmg file, and how to burn the .dmg file onto another CD/DVD.
Insert the CD/DVD with the file you want to convert into a CD-burning capable Mac.
Open Finder. Click on Applications, then double-click on the Utilities folder.
Double-click on Disk Utility to open the application.
In the Disk Utility window, go to the menu on the left and highlight the name of the disk you mounted.
Click on the File menu at the top of the screen. From the drop-down menu, click New, then Disk Image From [name of your disk].
Type a name for your new file, then navigate to the Desktop to save the file there.
Under Image Format, choose compressed.
Click Save. You now have a .dmg file saved on your desktop. Next, you can burn the file onto a blank CD/DVD.
Eject the original CD/DVD from the computer and insert a blank one. If you are prompted with a pop-up window, click Ignore.
Return to Disk Utility, and click the Burn button at the top of the window.
Navigate to the Desktop, and highlight the .dmg file you saved. Click Burn.
Click Burn again in the new window to accept default settings.
Once the program finishes burning the disk, it will automatically eject. You should now have a burned CD or DVD with a copy of the original file saved in .dmg format.