If you recently bought a new Mac, it is firmwared to the latest operating system that existed when it was designed. This means nothing to anyone who bought an iMac or Macintosh laptop. But if you bought a tower like the Mac Pro, then this is something you may want to learn more about.

The Mac Pro series from Apple is the preferred computer for graphic designers. Among other things, it features four available hard drive bays allowing users to add a few of their own hard drives. Graphic designers will often put in hard drives from previous Macs in these open slots. Some may even want to boot their Mac into an older operating system on one of these drives to use old PowerPC programs since they are no longer supported in Mac OS X Lion. This is where problems can occur.

If you plan to add a hard drive in your Mac Pro from an older Mac, be aware that some things may not work if you boot from an operating system older than Mac OS X Snow Leopard. The reason is because your new Mac Pro has been firmwared to the latest operating system available when it was designed. In most cases that’s Mac OS X Snow Leopard and above.

WHAT HAPPENS WHEN BOOTING FROM AN OLDER OS
So what will happen if you boot from an operating system older than Snow Leopard on a new Mac Pro. Well we did just that with a hard drive containing a 2007 version of Leopard. Here’s what we found. First, the power management didn’t work. That means the computer couldn’t go to sleep and when it tried to it froze up. The same was true of the screen saver. None worked with the exception of the “Computer Name” screen saver featuring the Apple logo. Some of the function keys on the keyboard didn’t match up. For example, the keys to control audio volume opened and closed the DVD tray. In general the display redraw was choppy, probably because the operating system didn’t have the right driver for the video card and was using something generic instead. Programs did open and close, but in general they ran slow and were unstable. More than a few times they froze up. And worst of all, the computer couldn’t shut down.

THE SOLUTION
So what’s the solution if you want to run your new Mac Pro from an older operating system? To avoid problems you should make sure you’re running Snow Leopard on any old hard drives you want boot from with your new Mac Pro. There are 2 basic strategies you can use to accomplish this.

STRATEGY 1 (Not Recommended)

1. Purchase a copy of Snow Leopard ($29 online from Apple)
2. Boot your computer from the old hard drive
3. Insert the Snow Leopard Install DVD and install
4. This method is marked “Not Recommended” because if something goes wrong you could loose the information on your hard drive. If, however, you don’t want to buy a new hard drive, this is the method you will have to use.

STRATEGY 2 (Recommended)

1. Purchase a new hard drive
2. Install the new hard drive in an open bay in your Mac Pro
3. Format the new hard drive as a boot drive (Mac Journaled)
4. Purchase a copy of Snow Leopard ($29 online from Apple)
5. Boot your computer from the old hard drive
6. Insert the Snow Leopard Install DVD and install on the new hard drive
7. Transfer settings from your old hard drive using the installer when prompted or by using Migration Assistant later
8. If you have Adobe Creative Suite on the old hard drive be sure to deactivate it and choose the “Erase Serial Number” option when you do. Otherwise you may run into problems activating the software.

The idea that a computer would be designed for the latest operating system just makes sense. It’s somewhat of a testament to the power of Apple’s operating system that an old OS would even boot up a new Mac at all. In the test described earlier, we were booting up a new 2012 Mac Pro from OS X Leopard which was release five years ago in 2007. The version of Leopard used had been updated with the latest Leopard software updates from Apple.