Apple is offering Mac users a free upgrade to OS X 10.6, better known as Snow Leopard, in an attempt to prep them for the June switch from MobileMe to the newer iCloud online sync and backup service.
Snow Leopard, which debuted in 2009, does not support iCloud -- only OS X 10.7, or Lion, does -- but with the free upgrade to the former, users will have to pay only one upgrade fee, the $29.99 for Lion, to use the service.
Lion is available through the Mac App Store.
The offer only makes sense for Mac users running OS X 10.5, aka Leopard, or earlier, on systems powered by Intel processors: Neither Snow Leopard or Lion support older PowerPC processor-equipped Macs.
About 18% of all Mac users, or fewer than one-in-six, ran Leopard or one of its predecessors last month, according to Internet metrics company Net Applications.
Apple will shutter MobileMe on June 30, a move it announced last year.
iCloud is a free service for Mac users running Lion, and for owners of any iOS device -- such as an iPhone or iPad -- running iOS 5 or later.
MobileMe, which cost users $99 per year, or $149 for a five-user Family Pack, has had a checkered history, stumbling badly during its 2008 launch, and was dogged by problems ranging from slow synchronization to extended email outages.
After MobileMe's launch debacle, Apple extended subscriptions by 30 days and turned the service over to a different executive. Then-CEO Steve Jobs also issued a blistering internal email to employees that said MobileMe was "not up to Apple standards" and that it had been a mistake to launch it alongside the debut of 2008's iPhone 3G and App Store.
Current MobileMe subscribers who switch to iCloud retain their email address, and their email, contacts, calendar and bookmarks are automatically migrated to the new service. Files stored on MobileMe's iDisk -- there's no comparable iCloud component -- must be moved to a Mac's or PC's local storage before June 30.
According to the Magasm blog, which yesterday reported the free Snow Leopard offer, Apple has been emailing MobileMe customers notifying them of the deal. Others can request a copy of OS X 10.6 by steering to Apple's website and signing in with the Apple ID linked to their MobileMe account.
The free copy of Snow Leopard will arrive on a DVD.
Apple is expected to launch its newest version of OS X, dubbed Mountain Lion, this summer.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is email@example.com.