Mountain Lion, Apple's next version of OS X (10.8), is due tomorrow. This means now's the perfect time to prepare your Mac for the smoothest upgrade transition.


This post was originally posted on July 19; re-posting in preparation for the imminent Mountain Lion release.


When Mountain Lion becomes available, you'll be able to download and install it from the Mac App Store for $19.99 and get it up and running in about 30 minutes. However, operating system upgrades aren't always so simple, so doing a few maintenance tasks beforehand can save you frustration later.

Before You Upgrade, Part 1: Find Out If Your Mac and Apps Are Compatible with Mountain Lion

Before you even think about getting all those great new features in Mountain Lion (such as the new Messages app, AirPlay Mirroring, and updates while your MacBook takes a "Power Nap"), you need to know if your computer meets the minimum system requirements. Most Macs sold in the last few years qualify, but Apple has tightened its requirements for this OS upgrade, and some older Macs—even ones that qualified for Lion—won't make the cut for Mountain Lion.

The general system requirements are straightforward:

OS X v10.6.8 or later

2GB of memory

8GB of available space

Apple also lists which models support Mountain Lion:

iMac (Mid 2007 or newer)

MacBook (Late 2008 Aluminum, or Early 2009 or newer)

MacBook Pro (Mid/Late 2007 or newer)

Xserve (Early 2009)

MacBook Air (Late 2008 or newer)

Mac mini (Early 2009 or newer)

Mac Pro (Early 2008 or newer)

Some new features, such as AirPlay Mirroring, require newer machines sold in the last year.


To find out if your Mac qualifies, click on the Apple in your menubar, then "About this Mac" and hit the "More Info..." button. The About this Mac summary window will show your model and release date, as well as the amount of memory installed to compare with the basic requirements. (Click the Storage tab to see if you have enough free space.)


One special note for Hackintosh people: Check Tonymac's blog post on getting ready for Mountain Lion for notes about additional requirements or potential issues.

If you have a Mountain Lion-compatible system, continue on. (If not, you could either think about upgrading your system or not worry about it—your version of OS X will continue to run just as fine as before, and Apple will likely still support it.)


Check if your apps are Mountain Lion-compatible

You'll also want to do a quick check to see if your favorite apps are compatible with the new OS. You can check individual softwares' websites to find out if the developers are planning to support Mountain Lion or go to RoaringApps for a broad list of compatible (and incompatible) apps. The list is growing and ongoing, though, so if your app currently has an incompatible status, keep in mind that most apps will eventually update to support Mountain Lion.


Before You Upgrade, Part 2: Clean Up and Optimize Your Hard Drive


Mountain Lion only requires 8GB of disk space, but even if you're not running out of room on your hard drive, it's a good idea to clear your Mac of all the useless applications, temporary files, and other space wasters so you don't carry them over to your new setup.

Our guide to speeding up, cleaning up, and reviving your Mac walks you through spring cleaning your Mac, including uninstalling apps you don't use and freeing up disk space, but, in short, here are the tools recommended for the task:


Remove apps you no longer need: AppCleaner

See which files are taking up all that space: Disk Inventory X DaisyDisk

Run disk maintenance utilities: OS X's built-in Disk Utility can make sure your hard drive is error-free. Head to Applications > Utilities > Disk Utility to verify and repair disk permissions and the disk itself.


For ongoing system maintenance, consider using a system optimization utility like our favorite Mac system tweaker, OnyX (the developers note that OnyX for Mountain Lion is in development now).

The Best System Tweaker for Mac If you want to tweak settings and run maintenance scripts in Mac OS X, you can always take it to… Read more


Before You Upgrade, Part 3: Back Up Your Mac


Actually, don't just backup your Mac—test that backup too. Backing up your Mac with OS X's built-in Time Machine is really easy: plug in an external drive and turn Time Machine on. Test the backups by doing a few restores of older and newer files to make sure you can recover your files if needed.


Optionally, you can clone your entire drive using our favorite tool for the job, Carbon Copy Cloner, so you can restore the whole system if worse really comes to worst.


Before You Upgrade, Part 4: Run System and Third-Party Software Updates


Regularly performing software updates is one of the few basic maintenance tasks you need to do for your Mac, and before an OS update it's especially important. Run the system updates by going to the Apple menu > Software Update.


At the very least, if you're running Snow Leopard (OS X 10.6), make sure you run Software Update so you're on the latest, minimum OS version, 10.6.8.

Before You Upgrade, Part 5: Organize Your iCloud-Related Files


Finally, while you're at it, now is also a good time to clean up your address book, calendars, photos, and other files that will be synced to Apple's iCloud online storage service. (Find out which services you have set up for iCloud syncing by going to System Preferences > iCloud.) This isn't really necessary for installing Mountain Lion, but the new OS places much more emphasis on iCloud storage for saving application settings and keeping your documents synced. You can get ahead of the game by weeding out the iCloud-related files you don't need so they don't take up more space than the 5GB free allotted.

We'll be covering Mountain Lion in depth once it's released, including alternate install methods, how to get the most out of the new operating system, and even whether or not you actually should upgrade. For now, though, it's a good opportunity to get your system freshened up and Mountain Lion-ready.