There were some legitimate disappointments in Apple Inc. (NASDAQ:AAPL)'s earnings last night. One of the most prominent ones was total Mac units, which came in at 4.06 million. Apple no longer breaks down the Mac business into desktops and laptops, but instead now only reports cumulative totals. Those Mac units were big drops both sequentially and year over year.

Source: Earnings releases.

This breaks a long streak of consecutive quarters where Mac growth has outpaced the broader PC market, which is a figure that Tim Cook likes to boast about. Apple Inc. (NASDAQ:AAPL) was up to 26 consecutive quarters, or 6.5 years, of trouncing the Microsoft Corporation (NASDAQ:MSFT) Windows competition. That time has now come to an end, and Apple Inc. (NASDAQ:AAPL) severely underperformed the broader PC market in the fourth quarter.

That's particularly discouraging considering how weak the PC market is right now, and Windows 8 also isn't doing much to stem the declining units. The 22% drop in Mac units from a year ago is far worse than the 6% decline that IDC estimated. While I didn't think it would hurt this much during the quarter, I did warn you that Apple's obsession could be a liability.

Cook warned you, too The newly redesigned iMacs have been controversial in some ways. The ambitious manufacturing processes used in the all-in-one desktop have never been applied to consumer electronics, and while they are incredibly thin, that has less value in a desktop machine that sits stationary all the time. Using friction-stir welding on the chassis and applying full display lamination on such large displays is no easy task.

In October, Cook warned that iMacs would be "significantly constrained" throughout the quarter, particularly with the 27-inch model. Those constraints are primarily what decimated total Mac units this quarter, with iMac units falling 700,000. In addition to that, Cook said that channel inventory was down from the beginning of the quarter by over 100,000 units.

Without these constraints, Cook would have expected Mac sales to be "materially higher."

Unveiling an unfinished product The new iMacs were introduced in late October at Apple Inc. (NASDAQ:AAPL)'s iPad Mini event, among other product unveilings. The whole timing of when Apple Inc. (NASDAQ:AAPL) began shipping them also points to how much difficulty the company is having in making them. For example, the prior generation iMac was introduced in the summer of 2011, making it an incredibly long product cycle until late 2012 -- twice as long as most previous iMac cycles.