How to Install OS X Mountain Lion From the Mac App Store [Video]

These are instructions on how to install OS X Mountain Lion 10.8 from the Mac App Store. The first steps in the video show the Mac App Store purchase, which Apple has replaced with the free download below.



Step One
On a Mac that can run OS X Mountain Lion, open Apple's How to download and install macOS page in Safari and click Mountain Lion 10.8 under 'Download via web browser'. The InstallMacOSX.dmg disk image downloads to your Downloads folder. Apple no longer sells OS X Mountain Lion in the Mac App Store; this download is free.


Step Two
Double-click InstallMacOSX.dmg to open it, then double-click InstallMacOSX.pkg and follow the onscreen instructions. This puts the Install OS X Mountain Lion app in your Applications folder. If the Mac isn't compatible with OS X Mountain Lion, the package won't complete.

Step Three
Open your Applications folder and double-click Install OS X Mountain Lion to open the install wizard. Click the Continue button to begin.


Step Four
Click Agree to accept the software license agreement.




Step Five
Make sure the correct hard drive is selected for installation and click the Install button.


Step Six
You will be asked to enter your administrative name and password. Enter these and click the OK button.


Step Seven
OS X Mountain Lion will prepare the installation. Your computer will restart automatically.


Step Eight
Once your computer restarts the installation will begin. This process can take from 15 minutes to an hour.


Step Nine
When the installation has completed successfully your computer will again reboot.


Step Ten
Once the system has finished restarting you are ready to begin using OS X Mountain Lion.