Note: This article was transferred from my original blog.
A lot more people have Macs today, which leads to a lot more people with a lot more questions. One frequent mix-up comes when a user needs to re-install Mac OS X or when someone wants to upgrade their copy of Mac OS X. Either they lose their discs or they decide to use one from a friend and they discover it just doesn’t work. They wonder why, that’s because not all discs will work with all Macs.
This happens because there are two common types of Mac OS X install discs. Three if you want to be specific. The first type is a Restore disc. These are gray-covered discs that come with your Mac when you buy it new. Usually there are two DVDs included, one has the Mac OS X software and the other has additional programs such as iLife. These discs will only work with that specific Mac model it was included with. For example a restore disc that came bundled with a MacBook will not work on an iMac. Or even a newer (2008) or older (2006) MacBook restore disc, may not work with your 2007 MacBook model.
The second type of a install disc is a Retail Install Disc. This is the type of disc you will buy from Apple. This is a full install disc and will work on any Mac that supports the minimum system requirements. It will install on an iMac, MacBook, Mac Pro, Mac Mini, etc. This version however does not include some bundled software that originally would of came with your Mac, such as iLife and some additional applications.
The third type of install disc is a variant of the Retail Install Disc, this is a Retail Upgrade Disc. These discs are usually received through Apple’s Up-To-Date program. You would receive this disc if you bought a Mac with the older software pre-installed on the system right after Apple has started shipping a newer version. For example if Mac OS X 10.5 came installed on your iMac and Apple released Mac OS X 10.6 a few days earlier, your iMac gets an upgrade. There may be a small charge to receive the updated discs. These discs will only install if it detects the older version of Mac OS X installed. For example it will not work on a Mac with no version of Mac OS X installed, or a version older then the previous version.
This can sound a bit confusing, but there is a simple way to tell the discs apart. A Restore disc has a gray cover and will say the model of the Mac it is for on the front along with a version number and a date. A Retail install disc will have a pretty graphic on the front and not mention a model such as iMac or MacBook. A Retail upgrade disc will look very similar to the Retail install disc, but it may say “CPU Drop-in DVD”, “Upgrade Disc” or “Update Disc” on it. This signifies that the install disc will check for a previous (and existing) installation of Mac OS X before it can install the updated version of the software, and will not work on a Mac that has no software on it.
So if you bought a new hard drive for your Mac and it’s blank, you will need a Retail install disc or the appropriate Restore disc for your Mac. An Upgrade disc will not work in this situation. Above is a graphic showing the difference between a restore disc and a retail install disc. I hope this helps with some confusion about the different Mac OS X install discs. Happy installing!!