Mac’s come with a built in tool called “Disk Utility” which can be used to clone your Mac Hard Drive. The process of creating a bootable clone of your Mac Hard Drive is fairly simple, but before we get into the nitty gritty of actually creating a bootable clone of your Mac Hard Drive, lets talk a little about the reasons and advantages behind doing this.
1. Great Way To Have A Functional Backup Of Your Entire System
By cloning your Mac Hard Drive, you are essentially creating a exact copy or backup of your entire Mac system, this includes Operating System files and the Users home directories. Not only that, since this is a exact copy of your Mac Hard Drive, you can even boot of the Clone Drive by simply having the Clone Drive plugged in and keeping the Options key pressed down during system boot-up.
2. Useful In Testing Applications And Trouble Shooting Issues
The Clone Drive can be used to test new applications or software updates before actually installing it on the primary system. Also, in case of a system problem, you could boot of the Clone and identify if the problem is software or hardware related.
3. Ready To Go Replacement Of The Primary Hard Drive
In case of a Hard Drive failure or corruption, you could be crippled for hours or even days before the primary Drive could be fixed and data restored. Instead, you now could be immediately back in business by simply booting of the Clone Drive.
Using Disk Utility To Clone The Mac Hard Drive
Okay, now that we have discussed the reason behind cloning your Mac Hard Drive, lets actually see how to do it. Every Mac comes with a built-in tool called “Disk Utility” has mentioned earlier, this is what we will use to clone your Mac Hard Drive. You will also need an external Drive. Make sure that the external Hard Drive you are using for this purpose is equal to or larger than the used space on the source Hard Drive you plan to clone. Also, make sure to backup any data on the external Hard Drive, since all data on the Drive will be erased.
Now with your external Hard Drive plugged in and “Command” Key and “R” Key pressed down power-on your system. This will boot your system in Recovery mode. The reason you do this is, since you are cloning your OS partition you do not want anything from being changed on the source Hard Drive, booting your system in Recovery mode achieves this. Once in Recovery mode, Launch “Disk Utility”.
Once in “Disk Utility”, select the OS partition from the left hand pane, which is usually the first partition under the first Hard Drive in the list. Then, click the “Restore” tab on the right hand pane. Here you should see your OS partition already selected in the “Source” box.
Next, select the target partition on your external Hard Drive, on which you want to create the clone, from the Left hand side pane and drag it to the “Destination” box. Once the target partition shows up in the “Destination” box, hit “Restore” and the cloning process will begin. Once complete you should have a fully bootable replica of your OS partition / Mac Hard Drive.
Assumption: Please note, that this article assumes you have a Mac Hard Drive with a single partition / volume. In case you have multiple partitions on the source Hard Drive and want all partitions cloned, then make sure to partition the target Hard Drive to match the partition structure of the source Hard Drive. For help with partitioning see my article “Partitioning A Hard Drive On Mac Running OS X Lion“. Once you have created identical partition structure on the target Hard Drive, you can clone each partition / volume using the method described above. Except OS partition, all other partitions can be clone while logged into the system.
It’s as simple as that. If you want to boot into your new clone, simply have the external Hard Drive connected and keep the “Options” key presses down during boot-up and select the Clone. Also, in case you want to restore a specific file from the clone, you could always access it from “Finder”, just like you access any external Hard Drive. And in case you have an unfortunate event like a Hard Drive failure or corruption, simply reverse the above process to restore the Clone to a new Hard Drive.
Update (30th March 2013): This article has been modified for clarity and to ensure accuracy.
Please see disclaimer.