Apple released OS X Yosemite on 16 October and it’s free for everyone. But downloading a 5+GB file on each computer will take some serious time and bandwidth. So, the best thing to do is to create a bootable USB drive installer and use it for all your Mac’s.

Before you begin

Be sure that your Mac can run Yosemite, for this check if your Mac can be found within the list below:

  • iMac (Mid-2007 or later)
  • MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later)
  • MacBook Pro (13-inch, Mid-2009 or later), (15-inch, Mid/Late 2007 or later), (17-inch, Late 2007 or later)
  • MacBook Air (Late 2008 or later)
  • Mac Mini (Early 2009 or later)
  • Mac Pro (Early 2008 or later)
  • Xserve (Early 2009)

Like Maverick, Yosemite will need 2GB of RAM and 8GB of free storage space for the installation. But if you want your computer to run faster, you can add more RAM.

1. Get an Apple ID
If you own an Apple software it’s hard to imagine that you don’t also have an Apple ID. But if you really don’t own one, it’s time to. Otherwise, you can’t download Yosemite from the Mac App Store. Again, Yosemite is free for everyone, you wouldn’t pay a cent for it. Create Apple ID

2. Download Yosemite
To get your copy, go to the OS X Yosemite page where you can download it for free. Click the button to download it and the enter your Apple ID and password when prompted. Then it will start downloading into the Applications folder at the root level of your hard drive. The file exceeds 5GB so if you have a slow broadband connection, be sure you’ll wait awhile. Download

3. Format USB drive
Make sure your USB flash drive is at least 8GBs in size, then mount it.

Run Disk Utility and follow the steps below:

  1. Select the USB Driver from the left menu (not the partition within it)
  2. Move to the Partition tab
  3. Change the Partition Layout to 1 Partition
  4. Give it a name (ex: Yosemite)
  5. At Format select Mac OS Extended (Journaled)
  6. Click on Options button somewhere at the bottom of the window
  7. Check GUID Partition Table and click OK
  8. Click Apply and then confirm by clicking Partition button

Wait to finish erasing and repartitioning your USB drive.

4. Mount image
Go to Applications and find the “Install OS X Yosemite” app, Right-Click on it and select Show Package Contents then navigate to Contents > Shared Support and open InstallESD.dmg, wait till it finishes to Verify and mount. Don’t touch the new window that opens.

5. Unhide all files in Finder
Open a Terminal and input the following two commands, hit Enter after each one.

  • defaults write AppleShowAllFiles TRUE
  • killall Finder

If all seems fine, you should see three more files, slightly grayed in the mounted OS X Install ESD window.

6. Restore USB Drive to BaseSystem
Open Disk Utility and select the Yosemite partition of the mounted USB flash drive from the list on the left, then:

  • Open the Restore tab
  • Now, drag and drop Yosemite partition from the list on the left, down to the Destination path
  • From those 3 files that we unhided, drag and drop BaseSystem.dmg to the Source path
  • Hit the Restore button

disk_restore yosemite

On the following prompt, click on Erase to initiate the restore process, then enter in your admin password and hit OK to proceed. Wait a few minutes after what you should see the OS X Base System window open.

7. Copy folders
In the OS X Base System, find the System folder and open it. Here, open the Installation folder. Head back to your OS X Install ESD window and drag and drop the Packages folder inside of the Installation folder.
Hit Replace to confirm and wait for it to finish copying over.

8. Copy files
Find the files BaseSystem.chunklist and BaseSystem.dmg in the folder OS X Install ESD (from where we just moved the Packages folder), copy them to the root of your OS X Base System partition folder.

9. Hide files in Finder
Open Terminal, write following commands and press Enter key after each one.

  • defaults write AppleShowAllFiles FALSE
  • killall Finder

Now close all windows, exit Terminal and Disk Utility, eject mounted disks. And that’s all.

How to install Yosemite on Computer?

We created the OS X Yosemite boot installer USB drive, now lets install Yosemite on our computer.

Plugin the bootable USB driver that we just created, restart computer and keep holding the Option (Alt) key on your keyboard. When the Startup Manager pops up, select OS X Base System volume (or whatever your bootable drive is called).

Make sure to select the right disk on which Yosemite will be installed, then just follow the install instructions.

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