Reference 4.3 External OS X Recovery Disks
In some cases, a Mac with OS X installed does not have a local OS X Recovery HD. For example, if you just replaced the internal disk with a new disk, nothing will be on the new disk. Also, OS X systems on RAID sets and disks with nonstandard Boot Camp partitioning will not have a local OS X Recovery HD. In these cases, you would need to start up from an external OS X Recovery disk. Also, having an external OS X Recovery disk handy can be a real lifesaver should you come across a Mac with a dysfunctional system disk.
Alternatively, two do-it-yourself solutions exist to convert a standard disk into an OS X Recovery disk. The first involves creating a minimal OS X Recovery disk using OS X Recovery Disk Assistant. The second solution creates a full OS X Recovery disk using the contents inside the Install Mac OS X application.
- Create a minimal OS X Recovery disk—The advantage to creating an OS X Recovery disk with this method is that it only requires a 1 GB USB flash disk. This method is fully supported by Apple as it’s initiated through the OS X Recovery Disk Assistant, available on the Apple support downloads website. The downside to this method is that the resulting OS X Recovery disk will not contain the OS X installation assets. Thus, when running OS X Recovery from this disk, if you need to reinstall OS X, the system will have to download the OS X installation assets from the Internet. Exercise 4.2, “Create a Minimal OS X Recovery Disk,” outlines the steps necessary to create this type of disk.
- Create a full OS X Recovery disk—The advantage to creating an OS X Recovery disk with this method is that it will include the full OS X installation assets on the disk. This method involves using Disk Utility to copy the Install OS X Mountain Lion application assets to an external drive. However, the downside to this method is that it requires an 8 GB disk. Exercise 4.3, “Create a Full OS X Recovery Disk,” outlines the steps necessary to create this type of disk.