OS X Mountain Lion is available now as a download from the Mac App Store. Just click the Mac App Store icon in your dock, purchase Mountain Lion, and follow the onscreen instructions to install it. Mountain Lion will not only make your Mac work better, it also makes your Mac work even better with your iPhone, iPad, and iPod touch. Because it comes with iCloud, your mail, calendars, contacts. OS X Version: Mountain Lion (10.8), most models. Mavericks (10.9) or higher — all models. How to check it: Click the Apple icon at the top left of your screen. Select 'About This Mac.' The number underneath 'OS X' is your version number. If you're running a version of OS X older than 10.8, look into upgrading your OS X.
Apple has loosed the Lion update unto the world and into the hands of feverish, excited Mac fans. Before you fork over your $30 for an upgrade license, however, be warned that Apple’s OS X updates tend to break some applications — and in the case of Lion, which deprecates some older Apple machines, you even need to make sure your hardware is supported before you run the installation.
Unlike Windows service packs or other applications that undergo minor version number bumps, like Chrome or Photoshop, OS X revisions are generally major overhauls that break functionality that some apps rely on. The version number might have only shifted from 10.6 to 10.7, but in actual fact it’s more like the change from Vista to Windows 7 — they look much the same, but there are under-the-hood changes that can cause incompatibilities and instabilities with your current applications. In some cases, application developers only need to release a new version of the installer — but in other cases, installed software will simply refuse to run under OS X Lion until an updated version is released.
Before you install Mac OS X 10.7 Lion, make sure you run through this list of preparatory precautions:
1. Make sure that your installed applications will work after the upgrade
RoaringApps is a community-powered site that has been testing application compatibility for OS X Lion over the last few months using the beta and final, golden master builds. There are a lot of compatible apps, and a large number of apps that haven’t yet been tested — but most importantly, there are tons of apps that are incompatible with OS X Lion.
For the most part, if one of your applications is marked as “incompatible” there isn’t much you can do except wait for an update from the developer.
2. Make sure your hardware will support OS X Lion
With the update from 10.6 to 10.7, Apple has deprecated any hardware older than 2006 — possibly in an effort to force upgrades, or perhaps just to ensure that OS X remains a smooth, Jobsian experience. If your computer does not feature an Intel Core 2 Duo, Core i3/i5/i7, or Xeon CPU, it will not run OS X Lion. This includes almost every Intel-powered Mac except for the earliest Mac Minis and MacBook Pros.
If you’re uncertain about your Mac’s provenance, click the Apple icon in the top left of your screen and then About This Mac. The Processor field will tell you what your computer has under the hood. If it isn’t a Core 2 Duo or newer, don’t try to install OS X Lion.
3. Run Software Update before you buy and install OS X Lion
It’s a simple step, but because OS X Lion is distributed through the Mac App Store, it’s important that you run Software Update beforehand to install bug fixes or prerequisite patches. Heck, if you’re still using an old version of OS X 10.6, you won’t even have the Mac App Store on your computer — so you really will need to run Software Update.
Click the Apple icon in the top left of your screen, Software Update, then follow the prompts.
4. Make a backup
Os X Mountain Lion 10.8.4
In the unlikely case that something goes wrong during the installation procedure, or if you discover that a vital application doesn’t work under the new version of OS X, you’ll wish you had a backup. Fortunately, Time Machine makes backing up and restoring your full system incredibly easy — as long as you have an OS X installation DVD, anyway.
Os X Mountain Lion Tips
Before you install OS X 10.7, run Time Machine and back up your system to an external drive, a NAS, a Time Capsule, or a DIY Time Capsule). The Apple support site has some tips on running Time Machine and how to perform a full restore of your system if something goes wrong.
5. Finally, disable encryption and verify the integrity of your hard drive
As The Next Web points out, OS X Lion introduces a new version of FileVault, and if you’re running the old version on OS X 10.6 you should probably disable it before upgrading.
You should also run Disk Utility (type “disk utility” into Spotlight), select Macintosh HD, and click Verify. This will verify the integrity of your hard drive and make sure there are no corrupt files that will get in the way of the upgrade procedure.
If you have any tips to help with migration from one version of OS X to the next, leave a comment!