Here’s a little tip if you’re missing the installation disks for your Mac and have another set handy from the same model or seriesl.

A couple of weeks back, a client asked me to reformat a couple of Macbooks. Both Macbooks were bought last year. The first was purchased in March 2008 (shipped with OS X 10.5.3), the second in June 2008 (shipped with OS X 10.5.4). Unfortunately, for me, the client had misplaced the installation discs for the Macbook he originally bought in March.

Not having the OS X 10.5.3 installation disks made reformatting the Macbook a much bigger headache than it should have been. While becoming increasingly frustrated, I forgot that installation disks that ship with Apple products (Macbooks, Macbook Pros, iMacs and so on) are all model specific. Upon reinstalling OS X, the installation disk will check your system to make sure it matches the embedded model profile settings on the installation disk. If everything matches, you can install a fresh copy of OS X on your Mac.

My problem is that I had two nearly identical machines, but only one set of installation disks handy. And for whatever reason, the installation disks that shipped with the Macbook bought in June of 2008 thought that the machines were different enough that OS X couldn’t be installed on the the slightly older Macbook from the available installation discs. I didn’t feel like calling Apple Care or heading over to the closest Apple Store to try to get replacement installation disks as I had had enough fun with Apple the last few months trying to get my iMac fixed.

So, I started to fiddle…

And how did I get around this problem? After fiddling around for a while and out of sheer desperation, I decided to connect the two Macs together with a Firewire cable, boot up the Mac purchased in March in Target mode and try to install OS X on the Target Drive. Thankfully, my little test worked.

Here’s a step by step of what I did:

1. Turned on the Macbook purchased in March (which didn’t have the installation disks handy) and booted into Target Disk Mode
2. Connected both Macbooks together using a Firewire 400 cable
3. I booted up the newer Macbook, loaded the OS X installation DVD and rebooted
4. Followed the installation instructions and made sure to install OS X on the Target Drive
5. The OS X installed disc checked the configuration (probably checking the hardware found on the local Macbook) and began to install on the hard drive of the Macbook purchased in March