The steps to install Snow Leopard onto an external hard drive are very similar to the steps of booting OS X from a USB drive. In fact, if you have a large enough USB flash drive, you can use these same steps to install Snow Leopard on to it. This 128 GB USB Flash Drive can service just as well as a normal External Hard Drive, and may even run a bit faster than your typical HD.
- Insert the OS X 10.6 Snow Leopard DVD into your Mac, or boot into the USB Snow Leopard Installation we described in an earlier post.
- Open system preferences from the menu bar, select start up disks and then the OS X 10.6 Snow Leopard Install DVD. Click the restart button to start the installation process
- After your computer restarts continue through the introduction and agreement pages
- The External Hard Drive won’t currently be an option for installation so we’ll need to use Disk Utility to make some configuration changes. Select Utility from the Menu Bar to access Disk Utility.
- Once Disk Utility opens, select the External Hard Drive you’d like to install Snow Leopard onto and then Select Partition. From here select 1 Partition and then click Options. To allow the Mac to boot from the external hard drive, the drive must be setup with a GUID Partition Table. Select GUID.
- To make sure that you don’t mistake the External Drive for your normal Hard Drive, be sure to name the Volume something like “Snow Leopard”. Apply the changes and continue to the next step
- Exit DisK Utility and the installation window will return asking which volume you’d like to install snow leopard onto. Select the External Hard Drive that we partitioned with GUID (Named Snow Leopard) to continue the installation. Follow the instruction until the installation is complete.
Once the installation to my External Hard Drive started, it took 30 minutes to complete. The total install time including setting up the External Hard Drive as a GUID bootable device took close to 40 minutes.
This time depends completely on your computer settings and hard drive speeds.
I’ll be the first to admit that I was amazed at the speed of the OS on the External Hard Drive. I expected Snow Leopard to run slower than the native hard drive but that wasn’t the case. Safari opened quickly, finder also was zippy, and the dock functioned without any speed issues. Moving files around and creating video with Quicktime X worked flawlessly.
It functioned so well that I’ve decided to do a fresh install on to my internal hard drive on my Mac. I’ll backup the data on the drive and follow the steps listed above but will select my internal hard drive as the volume.