When it comes to software that’s incompatible with the new version of OS X, the biggest offenders will likely be programs and system add-ons that integrate with (or hack) the OS at a low level. Kernel extensions, for example, are notorious for being incompatible with major new versions of OS X, but you may also find that utilities that tweak the Finder, add-ons that improve Mail, and other plug-ins and “enhancers” that work fine under your current OS installation won’t work under Mavericks. (This will be especially likely for people upgrading from Snow Leopard.) Since most of these types of apps and add-ons aren’t allowed on the Mac App Store, be sure to check vendor websites for OS X 10.9-compatible updates before upgrading. (Don’t forget to check third-party System Preferences panes, Mail add-ons, menu-bar apps, and Web-browser plug-ins.) If it turns out that a particular bit of software is incompatible with Mavericks and doesn’t have an update available, uninstall or disable that software until a compatible version is released.
Snow Leopard users only: Check for really old software If you’re still running Snow Leopard (OS X 10.6), you may have a few PowerPC programs—software that was never updated to run natively on Macs with Intel processors—on your drive. Under Snow Leopard and earlier versions of OS X, Apple provided software called Rosetta that allowed PowerPC code to run on Intel Macs. In Snow Leopard (OS X 10.6), Rosetta was no longer installed by default, but the OS would offer to download and install Rosetta if you tried to run a PowerPC program. However, Apple killed Rosetta completely when Lion (10.7) was released, and it remains unavailable in Mavericks.
This means that any PowerPC apps you’ve been using under Snow Leopard won’t work at all in Mavericks. If you have important PowerPC programs (for example, older versions of Quicken for Mac are still surprisingly popular), you’ll need to update those programs to Intel-processor versions, if available, before upgrading to Mavericks. If such updates aren’t available, you’ll want to find acceptable alternatives, whether those are modern Mac alternatives or, if need be, Windows versions that you can run under Boot Camp or virtualization software such as Parallels or Fusion. (Christopher Breen’s series of articles on Lion and PowerPC software remains useful if you’re still running Snow Leopard.) Alternatively, you could keep an old Mac on hand to run those apps when needed.
How can you tell which of your applications are PowerPC programs? The easiest way is to launch Snow Leopard’s System Profiler utility (in
/Applications/Utilities), select Applications (under Software in the sidebar), and then click the Kind column header, which sorts the list of applications by processor type. Any programs listed as PowerPC will not work under Mavericks, Mountain Lion, or Lion. (If you have any listed as Classic, that ship sailed long ago.)
Set up your iCloud account Apple’s cloud-syncing service, iCloud, is heavily integrated into many apps and system services. (This integration started in Lion, but it has become increasingly more prevalent with each major OS X update.) To avoid being hassled about iCloud syncing when you first log in to your new Mavericks installation, make sure that you’re logged in to your iCloud account, and that you’ve enabled syncing for the various types of supported data, before upgrading—you’ll simply need to provide your iCloud password once you boot into Mavericks. (If you’re upgrading from Snow Leopard and you don’t yet have an iCloud account, you’ll be prompted to create one once you boot into Mavericks for the first time.)
Suggestion: Have an extra drive handy While most people will simply install Mavericks over Mountain Lion, Lion, or Snow Leopard, there are situations in which you might want to install onto an empty drive. For example, if you want to install Mavericks on a second drive to test the OS before upgrading your main drive, or if you want to erase your Mac’s startup drive and start anew. (The latter might be a good idea if your Mac has been having issues, or if your drive is nearly full or in need of repair.) As I’ll cover in an upcoming article on installing Mavericks, installing it onto a secondary drive is simple. However, erasing your Mac’s startup drive and starting fresh requires that you have a good, tested backup (see above) as well as a bootable Mavericks install drive, so now’s the time to start preparing.
Ready to go
Thanks to the Mac App Store, the process of obtaining and installing major updates to OS X is easy and relatively quick—remember the days of optical disks and postal-mail delivery? But the better shape your Mac is in before you install OS X 10.9, the better your experience will be during and after the upgrade. Now that your Mac is properly prepped, you’re ready for our complete guide to performing the upgrade. We’ll be publishing a slew of articles on using and tweaking Mavericks, so stay tuned to Macworld.com.
Updated 10/22/2013, 3:45pm, for the release of Mavericks and our full install guide.