Creating a USB install drive is one of the simplest ways to ensure that a fresh clean installation of OS X Mountain Lion is only a few steps away. Gone are the clunky days of using CDs to reinstall an OS.

Inside, we’ll show you how to setup your very own OS X Mountain Lion USB installation drive, using an easy to follow video walkthrough.

Note: while some have stated that you can use a 4GB drive, and we were able to get a 4GB drive working fine with Lion, we ran into problems when trying to use a 4GB drive with Mountain Lion. Hence, we can only suggest that you use an 8GB drive instead.

Step 1: Download OS X Mountain Lion from the Mac App Store.

Step 2: Open the Disk Utility and erase the 8GB USB drive. I suggest naming it something recognizable, like “Mountain Lion Boot Drive”, “Mountain Lion USB Key”, etc.

Step 3: Open a new Finder window, and navigate to the Applications folder. Inside, you should see the following: Install OS X Mountain This is the Mountain Lion installation app that was downloaded from the Mac App Store. Right click on the app, and select Show Package Contents.

Step 4: Open the Contents folder, followed by the Shared Support folder, and locate InstallESD.dmg. Double click on the InstallESD.dmg image to mount the image. Afterwards, you can close any open Finder windows.

Step 5: Reopen the Disk Utility, and select the 8GB USB Flash Drive, then click the Restore tab.

Step 6: Drag the Mountain Lion USB Key to the box labeled Destination.

Step 7: Click the Source box, and then click InstallESD.dmg, which is below the USB drive in the left panel.

Step 8: Once you have verified that both the Destination and Source fields are populated with the correct info, click the Restore button in the bottom right corner.

Step 9: The Mountain Lion USB Installation drive will now be created. This step takes about a half hour depending on your system and drive. Just wait a while.

Step 10: If you receive a message that says: Restore Failure Could not restore β€” Invalid argument. Don’t worry, just ignore it and the USB Drive should be okay.

Step 11: Once complete, eject and remount the USB drive, and verify the presence of Library, Package, and System folders. Also, make sure that Install OS X Mountain exists on the drive as well.

Congratulations, you now have your very own OS X Mountain Lion USB installation drive that can be used at any time, and fit in that small 5th pocket in your blue jeans!

Tell us, how do you normally go about reinstalling OS X?

  • Hey Jeff once this is done can mountian lion be installed on a pc or no

    • I haven’t done a hackintosh in years, since Snow Leopard was first released, so I’m really not in a position to answer that, sorry. Perhaps someone else can?

    • Jim

      Lion DiskMaker 2.0.1 does all this for you πŸ™‚

      • True, but it’s good to know how to do it manually. That way you get a sense of the concept behind the process.

    • christodouluke

      I left you a link but since hackintoshing violates the EULA, maybe it won’t pass moderation, I don’t know. Just in case, check out Unibeast.

  • Very handy… im new to the Mac family. Im updating my new MacBook Pro with a ssd and i really needed to know this, Thanx man!

    • CollegiateLad

      If you have an external hard drive encloser, you can just clone your current setup to the ssd… That way you don’t have to painstakingly load all your apps, music, photos, etc. Just clone and switch hard drives.

  • This video is just a tad bit late lol, jk, thanks for the vid.

    • Yeah, it is admittedly. But we figured some people still might need it πŸ™‚

  • Simon

    When you have created the usb, it is possible to just boot it in the
    mac and make a clean start, when you installed lion everything old gets deleted?

  • Ali Shami

    Too late “”

  • Aaron de Silva

    Will installing OS X 10.8 this way delete everything on my Mac or will it install the same way as upgrading? And can I use this method to install on leopard (OS X 10.5)

    • It’s the exact same as if you were using a CD.

      • Aaron de Silva

        thanks! I’m trying to find a way to upgrade my Leopard. It’s very difficult to find a snow leopard upgrade these days.

    • CollegiateLad

      It will be like upgrading. If you want a clean install, boot into disk utility and erase the hard drive. After that, install OS X.

  • Dlevi309

    Haha this was on macdownloadblog right Jeff πŸ˜‰

  • CollegiateLad

    Yes. I’m a developer. My macs always have two partitions. One for the current OS, and the other for beta software. To me, it’s one of the safest ways to experiment with BETA OSes. Installing the betas over your primary OS is a bad idea. Dual booting is the way, mate!!!

  • I’ve purchased it downloaded and installed it and i don’t have the app in the app folder!! any ideas why not?? macbook pro early 2011 os 10.8.1

    • you have the system installed right? You dont need an app for it πŸ˜›

      • its whatever the app store did!

      • I think once you installed the system, the disk is erased and you have to redownload ML again.

    • i think the app is missing because you already INSTALLED it, the app/installer vanishes (into God knows where) after you’ve installed Mountain Lion. so you need to download again…at least thats what i think is happening to you.

    • Go into your Mac App Store and click purcases. Redownload it but do not run it again. You can then follow the tutorial to create the installation drive.

  • Can I use this bootable USB on a PC?

  • I really like the idea of merging relevant macbook news together with idevice news on your website. It makes sense and it will be beneficial.

  • Can any1 tell me or provide me a link to do this through a windows 7 pc??

  • Nicolas Loots

    Meh. I’ll stick with the Unibeast method.

  • So by doing this, can I transfer the OS to my macbook? My macbook currently is showing a question mark folder and I think it needs a new OS, thats why I am trying to do this.

  • Keith

    I followed your instructions but I get a message after I hitting the restore button that reads “could not restore – Resource busy”

    • Louie

      You have it open.
      Try closing all windows and click restore again.

  • goddard3100

    i keep getting “Could not restore – Resource busy” when trying to proceed on to step 9. any ideas i have redone your process 5 time. with no luck..

    • Louie

      You have it open still.
      Close all windows and click restore again.

      • kyteflyer

        Well no. I’ve been having the same issue. Its not open anywhere but I still get resource busy. I’m going to try a reboot. I’m doing this from Yosemite and its a royal pita.

  • Matt

    Finally, the correct way to do this. Thank you for stopping me from pulling my hair out. This worked flawlessly. And Mountain Lion installed in 18 minutes on my new SSD drive… woohoo

  • where to download mac os x free

    • Certain bays… frequented by pirates… that’s all I can say.

  • Worked great for me, so now I’m ready for my hard disk change to SSD πŸ˜€ Thanks!!!!

  • Anonyaisdosodaudsaiuddsad


  • Thanos Moraitis

    How about Mavericks Jeff???