Mountain Lion is almost here, arriving tomorrow on the Mac App Store. Are you ready to upgrade? First, make sure your Mac is Mountain Lion compatible.
Apple offers a list of technical specifications, so you'll be able to upgrade with confidence (although Apple says 2GB of RAM is OK, we'd recommend at least 4GB). If your Mac is from 2010 or newer, you are generally in the clear. Owners of older Macs will want to check upgrade specifics.
Purchase and download a copy of the installer from the Mac App Store. The installer should run about 4.5 GB more or less. We recommend that you copy the installer file to a safe place before you run it.
The installer is automatically deleted as part of the install process. That's not a problem if you've got lots of bandwidth in your life and don't mind downloading copies for each machine associated with your Apple ID. It is a problem if you live in New Zealand or rural Ohio or someplace else with metered Internet and intermittent connectivity.
Apple's recommendation, if you're bandwidth-limited, is to visit an Apple Store for downloading assistance; a Starbucks or internet cafe should be fine as well. As reported back in February, Apple has no published plans to deliver Mountain Lion on USB sticks.
Next, make a system backup. We recommend running Carbon Copy Cloner or Super Duper to prepare against any bad upgrade scenarios.
Finally, you're ready to get started with your upgrade. Just double-click the installer.
An upgrade typically takes under an hour and consists of a short install sequence followed by a reboot followed by a longer install sequence followed by another reboot.
The rule is this: have patience. You may need to wait 30-50 minutes for your upgrade to finish. So go take a walk, have a snack, or do Pilates. Keep your fingers away from the Power button and let the upgrade do its thing.
For many new Mac owners, the move to Mountain Lion represents your first major upgrade. To help users prepare to make the jump, Erica Sadun and Steve Sande wrote Getting Ready for Mountain Lion, an Amazon/iBooks eBook (US$4.99). It's aimed at first-time upgraders and people looking for hints and tips about smoothing the transition. They're sharing some of their tips on TUAW in a series of posts about the 10.8 upgrade.