For the first time in five years, PC shipments over the holiday shopping season were lower than the year before - and IDC is blaming Windows 8.
The research firm says that a hoped-for boost to sales from the new operating system failed to materialize, contributing to fourth quarter sales down by 6.4 percent, 4.5 percent in the US.
"Although the third quarter was focused on the clearing of Windows 7 inventory, preliminary research indicates the clearance did not significantly boost the uptake of Windows 8 systems in Q4," says Jay Chou, senior research analyst with IDC's Worldwide Quarterly PC Tracker.
"Lost in the shuffle to promote a touch-centric PC, vendors have not forcefully stressed other features that promote a more secure, reliable and efficient user experience."
IDC says it had expected the second half of 2012 to be difficult. Competition from tablets and smartphones diverted onsumers as well as PC vendors and distribution channels away from PC sales. On top of this, says the company, users were uncertain about the merits of touch on Windows PCs compared with tablets.
"As anticipated, the U.S. market had a rough ending, dropping 4.5 percent in the fourth quarter and contributing to a decline of seven percent for the full year 2012," says David Daoud, tracker research director.
"Consumers expected all sorts of cool PCs with tablet and touch capabilities. Instead, they mostly saw traditional PCs that feature a new OS (Windows 8) optimized for touch and tablet with applications and hardware that are not yet able to fully utilize these capabilities."
Some brands, though, managed to buck the trend - most notably HP, Lenovo, Asus and Samsung. And, says IDC, things are set to improve.
"As Windows 8 matures, and other corresponding variables such as Ultrabook pricing continue to drop, hopefully the PC market can see a reset in both messaging and demand in 2013," says Chou.