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Upgrade Install of macOS Mountain Lion
Move up to Mountain Lion without losing your personal data
By Tom Nelson Tom Nelson Writer Tom Nelson is an engineer, programmer, network manager, and computer network and systems designer who has written for Other World Computing,and others.
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Ethan Thomas Member
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Tom is also president of Coyote Moon, Inc., a Macintosh and Windows consulting firm. lifewire's editorial guidelines Updated on September 11, 2020 Tweet Share Email Tweet Share Email
In This Article
Expand Jump to a Section What You Need Step-by-Step: How to Upgrade Setting up Mountain Lion Updating the Software There are several ways to install macOS Mountain Lion (10.8).
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Sophia Chen 7 minutes ago
This guide will show you how to perform an upgrade install, which is the default installation method...
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Ryan Garcia Member
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This guide will show you how to perform an upgrade install, which is the default installation method. You can also perform a clean install, or install the OS from other media, such as a USB flash drive, a DVD, or an external hard drive. Those options are covered in other guides.
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Christopher Lee 3 minutes ago
Mountain Lion is the second version of macOS that can only be purchased through the Mac App Store. T...
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David Cohen 2 minutes ago
You may lose some apps that cannot run on Mountain Lion. The installer may also change some of your ...
Mountain Lion is the second version of macOS that can only be purchased through the Mac App Store. The upgrade install process lets you install Mountain Lion over your existing version of macOS and still retain all of your user data, most of your system preferences, and most of your applications.
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Ryan Garcia Member
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You may lose some apps that cannot run on Mountain Lion. The installer may also change some of your preference files because certain settings are no longer supported or are incompatible with some features of the new OS.
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Ava White 3 minutes ago
We recommend backing up your current system before starting the upgrade process. You can create a Ti...
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Sebastian Silva 1 minutes ago
Photo Geoffrey Kuchera / Shutterstock.
What You Need to Perform an Upgrade Install of OS X Mou...
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Mia Anderson Member
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We recommend backing up your current system before starting the upgrade process. You can create a Time Machine backup, a clone of your startup drive, or just back up your most precious files.
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Christopher Lee 11 minutes ago
Photo Geoffrey Kuchera / Shutterstock.
What You Need to Perform an Upgrade Install of OS X Mou...
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Ava White 2 minutes ago
Mountain Lion will install correctly as long as you're running OS X Snow Leopard or later. A destina...
What You Need to Perform an Upgrade Install of OS X Mountain Lion
A copy of the Mountain Lion installer, which is available from the Mac App Store. You must be running Snow Leopard or later to access the Mac App Store, but you don't have to install Lion before you install Mountain Lion.
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Mason Rodriguez 21 minutes ago
Mountain Lion will install correctly as long as you're running OS X Snow Leopard or later. A destina...
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Daniel Kumar 18 minutes ago
Basically, any bootable device will work, but because this is a guide to an upgrade install, the tar...
Mountain Lion will install correctly as long as you're running OS X Snow Leopard or later. A destination volume for the installation. The Mountain Lion installer can work with internal drives, SSDs (Solid State Drives), or external drives with USB, FireWire, or Thunderbolt interfaces.
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Nathan Chen Member
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Basically, any bootable device will work, but because this is a guide to an upgrade install, the target volume must be running OS X Lion or earlier. If your Mac doesn't meet this requirement, then the Clean Install guide is a better choice for you. A minimum of 8 GB of free space, but more space is better, of course.
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Noah Davis Member
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A minimum of 650 MB of free space for the Recovery HD volume. This is a hidden volume that is created during the installation.
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Kevin Wang 7 minutes ago
The Recovery HD volume contains utilities to repair drives and to re-install the OS if you have prob...
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Scarlett Brown 9 minutes ago
How to Upgrade Install macOS Mountain Lion
This guide will take you through an upgrade in...
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Hannah Kim Member
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The Recovery HD volume contains utilities to repair drives and to re-install the OS if you have problems with a drive. If you have everything lined up with current backups in place, you can proceed to the upgrade process.
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Brandon Kumar 30 minutes ago
How to Upgrade Install macOS Mountain Lion
This guide will take you through an upgrade in...
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Sophia Chen 14 minutes ago
While the upgrade process shouldn't cause any problems, it's always best to be prepared for the wors...
This guide will take you through an upgrade install of macOS Mountain Lion. The upgrade will replace the version of macOS your Mac is currently running, but it will leave your user data and most of your preferences and apps in place. Before you begin the upgrade, make sure you have a current backup of all your data.
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Aria Nguyen 1 minutes ago
While the upgrade process shouldn't cause any problems, it's always best to be prepared for the wors...
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Alexander Wang Member
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While the upgrade process shouldn't cause any problems, it's always best to be prepared for the worst. Launch the Mountain Lion installer. When you purchase Mountain Lion from the Mac App Store, it will be downloaded and stored in the Applications folder; the file is called Install OS X Mountain Lion.
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Julia Zhang Member
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The download process may also create a Mountain Lion installer icon in the Dock for easy access. Close any applications that are currently running on your Mac, including your browser and this guide.
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Lucas Martinez Moderator
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If you need to consult these instructions, you can print the guide or use a mobile device to read them. With the Mountain Lion installer window will open, select Continue.
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Sofia Garcia 45 minutes ago
The license agreement will appear. You can read the terms of use or select Agree to continue....
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Sophia Chen Member
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The license agreement will appear. You can read the terms of use or select Agree to continue.
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Evelyn Zhang 70 minutes ago
A new dialog box will ask if you've read the terms of the agreement. Select Agree....
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Henry Schmidt 68 minutes ago
By default, the Mountain Lion installer selects your current startup drive as the target for the ins...
By default, the Mountain Lion installer selects your current startup drive as the target for the installation. If you want to install Mountain Lion on a different drive, select Show All Disks, select the target drive, then select Install.
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Thomas Anderson 17 minutes ago
Enter your administrator password, then select OK. The Mountain Lion installer will start the instal...
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Victoria Lopez 20 minutes ago
When the process is complete, your Mac will restart automatically. After your Mac restarts, the inst...
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Sophia Chen Member
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Enter your administrator password, then select OK. The Mountain Lion installer will start the installation process by copying the necessary files to the selected destination drive. The amount of time this will take depends on how fast your Mac and the drives are.
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Harper Kim 89 minutes ago
When the process is complete, your Mac will restart automatically. After your Mac restarts, the inst...
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Lily Watson Moderator
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When the process is complete, your Mac will restart automatically. After your Mac restarts, the installation process will continue. A progress bar will display to give you an idea of how much time is needed to complete the installation.
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Christopher Lee 67 minutes ago
When the installation is complete, your Mac will once again restart. If you use multiple monitors, b...
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Ryan Garcia Member
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When the installation is complete, your Mac will once again restart. If you use multiple monitors, be sure to have all of the monitors turned on.
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Ella Rodriguez Member
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During the installation, the progress window may display on the secondary monitor instead.
How to Set up macOS Mountain Lion
When Mountain Lion is installed, either the log-in screen or the Desktop will appear, depending on whether you previously had your Mac configured to require log-in.
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Isabella Johnson Member
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If you did not have an Apple ID set up for your current OS, the first time your Mac starts up with Mountain Lion it will ask you to supply an Apple ID and password. Enter your Apple ID and password and select Continue, or skip this step by selecting Skip.
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Brandon Kumar 25 minutes ago
The Mountain Lion license agreement will appear. This includes the macOS license, the iCloud license...
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Daniel Kumar 21 minutes ago
Apple will ask you to confirm the agreement. Select Agree once again. If you don't already have iClo...
The Mountain Lion license agreement will appear. This includes the macOS license, the iCloud license, and the Game Center license. Read the information if you'd like, then select Agree.
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Apple will ask you to confirm the agreement. Select Agree once again. If you don't already have iClo...
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Ella Rodriguez Member
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Apple will ask you to confirm the agreement. Select Agree once again. If you don't already have iCloud set up on your Mac, you'll be given the option to use the service.
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Emma Wilson 22 minutes ago
If you wish to use iCloud, place a checkmark in the Set Up iCloud on This Mac checkbox, then select ...
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William Brown 78 minutes ago
If you choose to set up iCloud now, you'll be asked if you want to use Find My Mac, a service th...
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If you wish to use iCloud, place a checkmark in the Set Up iCloud on This Mac checkbox, then select Continue. If you don't want to use iCloud, or you'd rather set it up later, leave the checkbox empty and select Continue.
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If you choose to set up iCloud now, you'll be asked if you want to use Find My Mac, a service th...
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The installer will finish and present a Thank You display. Select Start Using Your Mac....
If you choose to set up iCloud now, you'll be asked if you want to use Find My Mac, a service that can locate your Mac on a map if you ever lose or misplace it. Make your selection by placing or removing a checkmark, then select Continue.
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The installer will finish and present a Thank You display. Select Start Using Your Mac....
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Update the Mountain Lion Software
Before you get busy with macOS Mountain Lion, you shoul...
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The installer will finish and present a Thank You display. Select Start Using Your Mac.
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Update the Mountain Lion Software
Before you get busy with macOS Mountain Lion, you shoul...
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You can find Software Update under the Apple menu. Was this page helpful? Thanks for letting us know...
Before you get busy with macOS Mountain Lion, you should run the Software Update service. This will check for updates of the OS and many supported products, such as printers, that are connected to your Mac and may need updated software to work correctly with Mountain Lion.
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You can find Software Update under the Apple menu. Was this page helpful? Thanks for letting us know...
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You can find Software Update under the Apple menu. Was this page helpful? Thanks for letting us know!
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Upgrade Install of macOS Mountain Lion GA
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Tom is also president of Coyote Moon, Inc., a Macintosh and Windows consulting firm. lifewire's edit...