It’s always good to have a backup of an operating system laying around in case you need to update an old computer or restore one quickly without Internet. Creating one may seem like an intimidating task, but it’s really not that hard.
You’ll need to be comfortable typing a few things into OS X’s Terminal, have an 8 GB or larger flash drive laying around, and 45-minutes to accomplish the task.
Before You Begin
You’ll need a few things before you can begin creating a recovery drive. Here’s a small checklist to run over first:
- OS X Yosemite install file (re-download it if your computer deleted it after installing the OS or make this recovery drive before you install the OS).
- An flash drive with 8 GB or more capacity.
- A computer running OS X 10.9 Mavericks or newer (that’s what I’m using for this tutorial, so I can’t guarantee it works on older versions).
- One hour.
Step 1: Formatting the Flash Drive
With the flash drive in hand, connect it and launch Disk Utility. Select the device in the left pane and click the Erase tab. In the Format field, you can select FAT or Mac OS Extended (Journaled).
Enter a title for the drive in the Name field. One word is best as OS X will change the name later anyway. When you’ve finished, click Erase and confirm by clicking Erase once more.
The drive is now ready for Yosemite’s image to be copied over.
Step 2: Terminal Commands
You’ll need to enter some commands into Terminal. Launch the app and follow the steps below.
- In Finder, navigate to the folder where the Yosemite install app is located.
- In Terminal, type
sudoand drag and drop the Yosemite app into the Terminal window. At the end of the file path, add
/Contents/Resources/createinstallmedia --volume /Volumes/YOURVOLUME -- applicationpath /YOURINSTALLAPP. Replace YOURVOLUME and YOURINSTALLAPP with the drive name and the Yosemite app path, respectively. For the path, you can drag and drop the app into Terminal just as you did before.
- Double check the command to make sure there aren’t any typos, then press Enter.
- Enter your password and press Enter.
- Erasing the disk takes a few seconds, but copying the installer files can take 30–45 minutes depending on the speed of your drive.
Step 3: Test It Out
Hopefully the command line process was successful and your drive re-mounted properly.
You can test it out by rebooting your Mac with the drive plugged in, holding Option, selecting the drive, and pressing Enter. This will boot from the drive. If all is well, you’ll be presented with a screen prompting you to install Yosemite.
In this tutorial, I’ve shown you how to create a recovery drive for OS X 10.10 Yosemite using one lengthy Terminal command and some time.
Now that you’ve got Yosemite on your computer and a recovery drive if anything goes wrong, there are lots of other tutorials for 10.10 that will get you started with its abundance of new features.