The latest instalment of the Macintosh operating system is the first since MacOS 10.4, which was released in April 2005 in what was Apple's most successful OS launch ever.
"Early indications are that Leopard will be a huge hit with customers," said Apple chief executive Steve Jobs.
"Leopard's innovative features are getting great reviews and making more people than ever think about switching to the Mac."
Leopard was launched worldwide at 6PM local time on 26 October. The new OS offers several interface upgrades as well as the new Time Machine backup system and the first finalised version of the Boot Camp Windows boot system.
The early success of Leopard comes at the end of one of Apple's best spring and summer sales periods in its history. Sales of Macintosh computers have risen by 33 per cent and 40 per cent yearly over the past two quarters.
However, although setting a MacOS record, Leopard still has a long way to go to take the all-time crown from Windows Vista.
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