If you intend on upgrading your Mac to OS X Yosemite, then I recommend you first save the installer that is downloaded to your Applications folder, as this can be used to directly install to other Macs you own. It also can be used to create a bootable OS X installation drive, which you can likewise use to upgrade other Mac’s, or better yet, reinstall OS X from scratch if needed.
Making a bootable installer drive is primarily useful for saving bandwidth and time when performing a clean OS X installation. Installing Yosemite will update your Mac’s recovery partition you can perform a clean installation of Yosemite, but this will need to download the 5+GB of installation files. In addition, if your recovery partition is corrupted and will not load, then you will need to use Internet recovery which will install the version of OS X that came with your Mac, then require you to again download the Yosemite installer.
To avoid the need to download many gigabytes to perform a clean installation, having a bootable USB drive can be handy, and with the OS X Yosemite installer application on hand, is quite easy to do.
- Use Disk Utility to partition an 8+GB USB drive (flash, or conventional) with a GUID partition scheme (done by selecting the drive, then selecting “1 Partition” from the menu in the Partition tab, and using the Options button below the partition graphic to set the scheme to GUID — see here for how to do this).
- Open the OS X Terminal (in the Applications > Utilities folder) and type “sudo” followed by a single space (do not press Enter yet).
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Open a new Finder window, and position it next to the Terminal window for convenience (you will be dragging items from this Finder window to the Terminal window).
- In the Finder, go to the Applications folder and locate the “Install OS X Yosemite” application that was downloaded from the App Store.
- Right-click (or hold the Control key when clicking) the installer and choose “Show Package Contents” from the contextual menu (this option should be at the top of the menu).
This is the command file within the Yosemite installer, which will need to be dragged to the Terminal window in the next steps.
- Go to the Contents > Resources directory in the window that shows up, and drag the file called “createinstallmedia” to the Terminal window.
Dragging the “createinstallmedia” file to the Terminal window will enter the full path to it.
- In the Terminal, type “--volume” followed by a space, then drag your USB drive from the Finder to the Terminal window (if needed, press Shift-Command-C in the Finder window to reveal the top-level of your computer that shows your mounted drives).
As with the command file, dragging your destination drive to the Terminal window will enter a full path to it.
- Return to the Terminal and type “--applicationpath” again followed by a space, and then drag the “Install OS X Yosemite” program from your Applications folder to the Terminal window.
Dragging the Yosemite installer application to the Terminal window to enter the path for it will complete the command, and you can press Enter to execute it.
- Press Enter to execute the command, and provide your password when prompted (it will not show). Then press “Y” at the prompt to confirm you wish to erase the drive and copy the installation files to it.
The command’s progress will be shown for a short while, and when it says “Done” you can eject the drive and use it to install OS X Yosemite.
- Wait for the command to finish. This will take a few minutes, during which it will update you on various steps of the process, and after which it will state “Done” and return you to the command prompt.
When all these steps are complete, your USB drive will be bootable. You can now test it by restarting your Mac with the Option key held down, and you should see it in the boot menu listed along with your main boot drive as a possible boot volume.
I have always done it with three steps: just open the installer, select the destination disk and install. Am I missing something?
I’ve gone to the trouble of making bootable install disks in the past. But, like you, I found it easier to just double-click the installer and run it. I keep the installers for OS X 10.7 onward on a separate hard drive. It doesn’t have to be bootable, just mountable. That way I don’t have to copy the installer to the drive on which I’m going to install it. You could put the installers on a large thumb drive, though. That would be more portable. Making a thumb drive bootable is OK, but it boots agonizingly slowly – if it boots at all. Sometimes it doesn’t. And thumb drives are easily lost and the data on them is easily corrupted. They’re great for moving files around, but they’re not really suitable for archive purposes. Of course if you create a bootable thumb drive and it won’t boot, as long as it mounts you can still access the installer.
If you’re not as enamored with Terminal as Topher is, there are easier ways to create a bootable installer. There’s a fine free app, DiskMaker X (https://www.macupdate.com/app/mac/39701/diskmaker-x), that I’ve used to create several bootable installers – after first doing it the hard way. There is a Yosemite version in development.
I don’t mean to put Topher down, but many of us, perhaps most of us, are not all together comfortable with Terminal. While there are some things that can only be done in Terminal (lots of things if you’re a fan), I prefer to use an app with a GUI to do as much as possible. And there are plenty of those to choose from, some with modest capabilities (and more ease of use) and others with vast powers to tweak the system. Among other things, these apps reflect the changes you’ve made (they’re recorded in labeled switches of one kind or another) and generally make it easy to restore defaults.
To each his own, of course.
I have install flash drives for Lion, Mt. Lion, and Mavericks. I don’t remember ever using the Terminal to create them.
A couple of points.
1 The typed-in commands begin with a double hyphen, as in “- -volume” (but without the space between the hyphens). You can see that in the screen-shots but in the text they look like a single dash.
2 Terminal sometimes seems to have problems with spaces and punctuation characters. I first called my backup disk “Install OS X 10.10” and the script wouldn’t run. Changing it to “InstallYosemite” solved the problem.
The site has a habit of auto-formatting text, which can be a frustration at times. I have updated the article, so the hyphens should appear properly now. Using dots or forward slashes in filenames is not recommended (and sometimes prevented).
Thanks again, Topher. Excellent guide (as usual).
Hi, Topher.
Excellent walk-through. The –volume and –applicationpath items, while correct in the Terminal screen shots, appear as -volume and -applicationpath in the explanation.
For those of you that don’t see the value in this walk-through… you probably don’t need to use this process. Whatever works for you is great.
For those of us that do see the value in this, many thanks, Topher.
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia -volume /Volumes/Naamloos –applicationpath /Applications/Install\ OS\ X\ Yosemite.app
Password:
You must specify both the volume and install application path.
What am I doing wrong here?
In your command you have a single dash before “applications” and “volume”…you will need to use two dashes before both of these, as described above.
Update: the app I had previously used to create bootable OS X instal disks, DiskMaker X, doesn’t work reliably for Yosemite. And the developer seems to have lost interest in the project with version 4b4, which has not been updated since October of last year. So I returned to this article to do it Topher’s way.
The first time I tried it, Terminal wouldn’t let me insert a space in what turned out to be a critical location (aren’t they all?) and the procedure failed to run. So instead of copying and pasting Topher’s code, I typed it directly in Terminal and was able to get the syntax right.
And, lo, it worked. I was a little concerned at first because the Utilities folder didn’t show up on the disk, as it did when using DiskMaker X, but apparently it was just invisible. I was able to boot from the install partition (which I used instead of a thumb drive); I didn’t run the installer, but I did use Disk Utility. So all is well. I’ll be saving this article for future reference, as I do with many of Topher’s tutorials.