iPhone soaked up engineering resources, causing 4-month delay for Leopard.
Apple will delay the release of its OS X 10.5 "Leopard" operating system until October.
in order for the iPhone to be released on schedule this June, Leopard had to be put on the back burner.
"iPhone contains the most sophisticated software ever shipped on a mobile device, and finishing it on time has not come without a price; we had to borrow some key software engineering and QA resources from our MacOS X team," the company explained.
Leopard was originally slated for release at June's Worldwide Developers Conference. Instead Apple now plans to offer attendees a beta version of the new OS at the event, with the full version shipping in October.
"While Leopard's features will be complete by [June], we cannot deliver the quality release that we and our customers expect from us," said the company.
Rumors of the delay began to surface late last month, at which time Apple denied the reports and maintained that the OS would be shipped on time.
Still, Apple remains unapologetic about the decision to make one major summer release at the expense of another.
"We think it will be well worth the wait," said the company.
"Life often presents tradeoffs, and in this case we're sure we've made the right ones."
Leopard promises several new components, such as Apple's TimeMachine backup application and a new interface system known as 'Spaces'.
Leopard will also sport the final version of the Boot Camp technology that lets Mac computers run Windows, as well as a retooled OpenGL system optimized for multi-core processors.