Step 3: Download OS X 10.10 Yosemite from Mac App Store. Once downloaded, quit the installer and make sure that the OS X Yosemite installer that you downloaded from the Mac App Store, is in Applications folder, and set to its default name; ‘Install OS X Yosemite.app’. Step 4: Start Terminal, type in the following code, and hit Enter. Very shortly, in this article, we show 3 possible ways to download Yosemite 10.10.DMG, then convert Yosemite.DMG to Yosemite.ISO (available solutions in both Mac OS X and Windows). I recommend making one for Yosemite, on an external hard drive or USB thumb drive, for many of the same reasons I recommend making a bootable Mavericks installer.
By Michael Argentini
Managing Partner, Technology and Design
Install Os Yosemite Dmg
How do you erase your Mac hard drive and install OS X Yosemite without a startup disk? Normally the answer would be to boot into recovery mode. But what if you need to partition the hard drive, wiping the recovery partition? You need a bootable OS X Yosemite installer. Here's how to make one using Apple's built-in boot drive creation tool.
What You Need
The Easy Option: DiskMaker X. The easiest way to burn Yosemite onto a disk is through a free app called DiskMaker X. Download the Yosemite installer and DiskMaker X, if you haven't already.
- The 5GB OS X Yosemite installer app that downloads into your Applications folder when you first install it via the Mac App Store. The file name is Install OS X Yosemite. After you upgrade to Yosemite, this file is deleted. So you have to quit the installer once it appears in order to keep this file.
- A flash drive, external hard disk, SD card, or the like, with at least 8GB of capacity.
- Your Mac user account must be an Administrator. If it isn't, go to Users & Groups in System Preferences and assign Administrator to your user account. You can change it back to a standard user when you're finished. You can also sign in to your Mac as the administrator to create the bootable drive.
Step 1: Format Your Drive
First, you must partition and erase the drive so that it can be bootable. To do this, launch Disk Utility and choose the destination drive in the drive list (left column). On the right, in the Erase tab, choose to format the drive as Mac OS Extended (Journaled). These are the defaults, so just confirm the settings.
Next go to the Partition tab and under Partition Layout choose '1 Partition' in the dropdown menu. Change the name from 'Untitled 1' to 'Untitled'. This is so that the Terminal command below will find the drive. Once the process is complete, the drive name will be 'Install OS X Yosemite'.
Click the 'Options' button. In the dialog that appears, choose 'GUID Partition Table' as the partition scheme, then click 'OK'. Again, this is the default, so just confirm the setting.
Finally, click 'Apply' to confirm the settings and prepare the drive.
Step 2: Make the Drive a Yosemite Boot Installer
In a single command you'll create the bootable install drive. Pretty sweet! To do this, launch Terminal and enter the following command. Note, this assumes that you haven't moved the installer out of your Applications folder. If you have, simply replace '/Applications' with the location of the installer:
The sudo command will ask for your password. As you type it will not appear. This is normal. Just enter it and press return to create the boot drive.
During installation, you'll see a progression of status messages.
Wait until you see a status of 'Done.' When you do, you can safely eject the drive and quit Terminal.
Step 3: Start Up from the Install Drive
If you open the new bootable drive in the Finder, you'll notice that it appears empty, other than the Install OS X Yosemite app. No worries. The boot files are hidden, and the installer app allows you to upgrade without booting from the drive if you don't need to.
To boot from this new installer, shut down the Mac, plug in the bootable drive, and hold down the option key while powering back up. You should eventually see a series of bootable drives. Click on the one named 'Install OS X Yosemite' and press the return key.
Where to next?
As with last year, there are two ways to get it done. There's the super easy way with the graphical user interface and the only slightly less easy way that requires some light Terminal use. Here's what you need to get started.
:max_bytes(150000):strip_icc()/YosemiteInstallerESD-585ae0465f9b586e020178d4.jpg "Macos yosemite usb installer")
- A Mac, duh. We've created Yosemite USB from both Mavericks and Yosemite, but your experience with other versions may vary.
- An 8GB or larger USB flash drive or an 8GB or larger partition on some other kind of external drive. For newer Macs, use a USB 3.0 drive—it makes things significantly faster.
- The OS X 10.10 Yosemite installer from the Mac App Store in your Applications folder. The installer will delete itself when you install the operating system, but it can be re-downloaded if necessary.
- If you want a GUI, you need the latest version of Diskmaker X app—we wrote this article based on version 4 beta 2, but if a 'final' version is released alongside Yosemite we'll update the article. This app is free to download, but the creator accepts donations if you want to support his efforts.
- An administrator account on the Mac you're using to create the disk.
The easy way
Once you've obtained all of the necessary materials, connect the USB drive to your Mac and run the Diskmaker X app. The app will offer to make installers for OS X 10.8, 10.9, and 10.10, but we're only interested in Yosemite today.
AdvertisementDiskmaker X has actually been around since the days of OS X 10.7 (it was previously known as Lion Diskmaker), but it's more important now because Apple has made alterations to the installer that prevent easy USB drive creation using the built-in Disk Utility app. It's still possible to create a disk manually using a Terminal command (which we'll go into momentarily), but Diskmaker X presents an easy GUI-based way to do it that is less intimidating to most people.
Make A Yosemite Boot Usb
Select OS X 10.10 in Diskmaker X, and the app should automatically find the copy you've downloaded to your Applications folder. If it doesn't detect the installer (or if you click 'Use another copy'), you can navigate to the specific installer you want to use. It will then ask you where you want to copy the files—click 'An 8GB USB thumb drive' if you have a single drive to use or 'Another kind of disk' to use a partition on a larger drive or some other kind of external drive. Choose your disk (or partition) from the list that appears, verify that you'd like to have the disk (or partition) erased, and then wait for the files to copy over. The process is outlined in screenshots below.
Mac Os Yosemite Download
The only-slightly-less-easy way
If you don't want to use Diskmaker X, Apple has actually included a terminal command that can create an install disk for you. Assuming that you have the OS X Yosemite installer in your Applications folder and you have a Mac OS X Extended (Journaled)-formatted USB drive named 'Untitled' mounted on the system, you can create a Yosemite install drive by typing the following command into the Terminal.
sudo /Applications/Install OS X Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install OS X Yosemite.app --nointeraction
The command will erase the disk and copy the install files over. Give it some time, and your volume will soon be loaded up with not just the OS X installer but also an external recovery partition that may come in handy if your hard drive dies and you're away from an Internet connection.
Whichever method you use, you should be able to boot from your new USB drive either by changing the default Startup Disk in System Preferences or by holding down the Option key at boot and selecting the drive. Once booted, you'll be able to install or upgrade Yosemite as you normally would.