How to Create a Disk Image in Mac OSX

By Techwalla Contributor

How to Create a Disk Image in Mac OSX. A disk image is a file that contains the contents of a DVD, CD or even hard drive. It is a convenient way to back up the data found on disks or transport the contents of a disk electronically. OSX commonly uses .CDR and .DMG files. A .CDR file can be renamed with the .ISO extension and used by Windows equipped PCs.

Step 1

Insert the disk to convert into the disk drive. Wait for the computer to identify the disk, and add an icon for it on the desktop.

Step 2

Double click the Macintosh HD (or main hard drive) icon. Select "Applications" and finally double click "Disk Utility" under "Applications."

Step 3

Select the disk from the list of hard drive(s) and disks on the left. There should be a small disk icon and then the name of the disk; it appears under a small disk icon with the name of the CD/DVD drive.

Step 4

Choose "New Image" from the icons at the top of the window once the disk name is highlighted. It should appear as a drive icon within a page icon with a green and white plus sing in the top right corner.

Step 5

Create a .CDR file by choosing "DVD/CD Master" from the Image Format selections. Give the file the desired name in the "Save As:" panel. Any other selection will create a .DMG file.

Step 6

Convert a .CDR file to an .ISO file simply by clicking on the file name twice (not double clicking) so that the name is highlighted with a cursor. Erase CDR, and type "ISO." Press "Enter," and the file is ready for use by Windows-based computers.