Apple provides a special app that turns any removable storage into a recovery tool. In the event of a disaster it means you can restore your Mac from a Time Machine backup, or run Disk Utility to repair disk errors. You can even entirely reinstall OS X. All that happens is the existing recovery area on the Mac’s hard disk – which is accessible at boot-time by pressing Cmd+R – is copied to the storage device. A USB memory stick is the obvious tool of choice but you can use an SD card if your Mac has a built-in card reader, or even an external hard disk.
Note that existing data on the device is wiped, and that the recovery disk can only be used with the Mac that created it. With that in mind, let’s get started with this nine-step tutorial.
Step-by-step: Create a portable recovery drive
1 Insert the stick
Open Disk Utility (it’s in the Utilities folder of Applications) and insert your USB stick. It should appear on the left. Select it, then select the Partition heading.
2 Create the partition
Under the Partition Layout heading, select 1 Partition from the drop-down list. Click the Options button beneath and click the GUID Partition Table heading, then OK.
3 Re-partition a disk
If you’re using a hard disk, you can keep data on it by shrinking the partition and adding another for recovery. This step isn’t for beginners but guides are available online.
4 Choose the format
Click the drop-down list alongside Format and select Mac OS Extended (Journaled). Type a name into the field, then click Apply. Click the Partition button in the dialog.
5 Download the installer
Once formatting has finished, head to http://support.apple.com/kb/DL1433 and download the Recovery Disk Assistant. It doesn’t install – just run it from the .dmg archive.
6 Start Recovery Assistant
Recovery Disk Assistant will instantly detect your USB stick, although you might have to click it. Select it, and click Continue. You’ll be prompted for your password.
7 Write recovery data
The data will now be written to the disk, which should take only a short while. Don’t remove the USB stick unless prompted to and don’t power down your computer.
8 Using the stick
To use the new recovery stick, insert it and reboot. Before the Apple logo appears, hold down Opt/Alt. Now click the orange USB icon, or use the cursor keys to select it.
9 Using recovery
Once the recovery system has booted, make your choice from the options. Perhaps the most useful tool is Disk Utility, which repairs errors that might prevent your Mac from booting.
In-depth: What to look out for
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