Make disk images from installation CDs before it’s too late
Mac Tip #542, 27 June 2012
If you buy a new Mac and want to install software you have on a CD or DVD you may find you can’t. Here’s why and how to deal with the problem before it’s too late.
Disk or disc? I use both forms interchangeably below. Apple reckon there’s a distinction, but really, who has enough time in the day to worry about it? I don’t.
- Insert a CD or DVD in your old Mac.
- Open Disk Utility.
- Select the disc and click the New Image button.
- Select a location for saving the disk image.
- Wait while the disk image is created.
- Eject the CD or DVD and store the disk image somewhere safe, ready for the new Mac.
If this Tip was useful, please leave a comment letting us know. Want more detail? Read the full Tip below.
Got installation discs?
If you’ve been using Macs for a while, you may well have bought some software that came on a CD or DVD. And if you’re sensible, you’ll have stored that CD or DVD in a safe place, in case you need to install the software again for some reason.
My personal collection includes iWork and Aperture, among others.
These days, of course, software is commonly delivered via the Internet, including through apple’s App Store. This Tip solves what may be a transitional problem.
Some new Macs don’t have disc drives
Let’s imagine that you buy a new Mac and of course you want to reinstall that software. Now you might have a problem. You see some of the newest Macs don’t include an optical drive.
Disk Images are virtual copies of physical discs
Examples of Macs without optical drives are the MacBook Air and the new MacBook Pro with Retina display. So here’s a tip for something to do before you dispose of your old Mac: make disk images from your installation CDs and DVDs. It’s easy, and here’s how.
Note: a disk image is just like a CD or DVD but without the plastic. It’s a sort of pretend plastic disc.
Make a disk image with Disk Utility
Every Mac includes an app called Disk Utility, so everyone can easily do this. Making a disk image is extremely simple. It takes only a couple of clicks and some waiting time.
Disk Utility. The Disk Utility window appears.
- Insert the installation CD or DVD into the drive on your computer.
- After a few moments the disc you inserted should show up on the left-hand side of the Disk Utility window.
- In the Disk Utility window, select the name of the disc you inserted.
- In the toolbar of the Disk Utility window click the
New Imagebutton. A dialog box appears where you can choose where to save the disk image.
- Select a location and click the
Savebutton. Now your Mac has a lot of work to do so go and make a cup of tea or take the dog for a walk.
Disk Images can be quite large. If you have limited Internet capacity avoid saving the disk image in a folder that’s automatically synchronised via the Internet (such as Dropbox). A good place to save a disk image is on an external hard drive.
How to use a Disk Image
You may have already used disk images if you’ve bought software online. The filename usually ends in the
Can’t see filename extensions such as
.doc? See the Related Tips section below.
- Find the
.dmgfile and double click it. The disk image mounts just like a CD or DVD.
- Click on the disk image where it’s listed in the Finder sidebar. The window for the disk image opens.
- Double click the installer file shown in the window, or follow whatever other instructions came with the original install disc.
- When you’ve finished with the
.dmgfile eject it by clicking the Eject arrow beside its name in the Finder sidebar.
.dmg files of install discs you can store the files on backup hard drives and then reinstall software any time without needing to use the physical disc. And that includes when you buy a new machine that doesn’t have a disc drive.
These older MacTips may also interest or help you:
- How to Set Finder Advanced Preferences
- Don’t Hide the Extensions
- The Software Series: Find and install software
- Tune up a new Mac
Please let us know how this Tip helped you. To leave a comment if you’re reading this by email or RSS feed please visit the Tip at the MacTips website. There should be a link from the title.