Apple will not offer a USB or Optical Disk external installer to Mountain Lion (as far as we have heard). That does not mean you cannot sneaker net the install around your home, office or lab like Apple Store employees do (sometimes). Lion Diskmaker has been updated to allow you to make a bootable USB or SD Card installer on a 8GB piece of media.

The process is straightforward:

1. Download Mountain Lion from the Mac App Store (Note: the default install deletes the installer image after installation, so you will need to re-download it from Mac App Store/Purchases if you already deleted it.)

2. Download the latest version of Diskmaker (4MB), and then open it. Select “Mountain Lion (10.8)”.

3. It should find the image. If it does not, browse to the image in your applications folder (or wherever you moved it), and then select “Create a boot disk”.

(Amazon has a great selection of 8GB and up USB Sticks and SD Cards starting at $4.99, by the way.)

4. Make sure your 8GB or greater USB Stick/Drive/SD card is mounted. Choose partition and go.

On a Retina MacBook Pro with a 8GB SD Card, the process took about 10- to 15 minutes. From there, you can install local copies of Mountain Lion, even from scratch, without having a 4GB download each time. That saves a lot of time if you have many machines to update or do not have broadband.

If you have any issues or want to make a donation (recommended), visit Diskmaker’s website.

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