Falling global demand for personal computers (PC) saw shipments fall by a record 10.6% in the fourth quarter from a year ago, according to market research firm IDC.
About 71.9 million units were shipped in the period, which includes the key Christmas shopping season.
IDC said the decline was the worst since it started tracking PC shipments.
PC demand has been hit by competition from smartphones and tablets, along with longer lifecycles for PCs.
Shipments fell in all regions around the world and have declined for five quarters in a row, according to IDC's figures.
Rival research firm Gartner also said shipments were down. Using different methodology, it saw a fall of 8.3% in the fourth quarter from a year ago.
Dave Lee, North America Technology Reporter, San Francisco
It doesn't take much analysis to work out why PC shipments are falling rapidly. I mean, look around you. If you're at home, what do you have in the corner where your PC used to go?
Then again, you're more likely to not be at home. The majority of visitors to this website, and most other major sites and networks, arrive there using their mobile devices.
And that leaves the workplace, the domain where PC is still king, and will remain so for a while yet.
Sales tanked in the last quarter, sure, but analysts expect the PC market to pick up again in 2016 as companies start to upgrade to Windows 10, which launched in the middle of last year.
Unlike home users, who could update in a few hours or so, big firms need to plan well ahead - and so many would have held off until the new year.
It'll mean a boost for traditional PC sales, but not a halt in their overall long-term decline.
Instead, IDC notes that sales of computers with detachable tablets, like Microsoft's Surface, are growing quickly (albeit from an almost standing start).
Other factors that contributed to the decline in shipments included economic issues such as falling commodity prices, weaker currencies, turmoil in financial markets driven by China, as well social tensions in the Middle East.
Apple was the only top five PC maker to see shipments grow last year, up over 6%, while Acer saw the biggest fall, of more more than 18%.
"Consumer sentiment toward PCs remains a challenge, though clearly there are pockets of growth," said IDC research manager Jay Chou in a statement.
"Even as mainstream desktop and notebooks see their lifetimes stretched ever longer, Apple's emergence as a top five global PC vendor in 2015 shows that there can be strong demand for innovative, even premium-priced systems that put user experience first."
Chinese tech giant Lenovo, however, remained at the top of the market - owning more than 20% of it. HP followed in second place, with Dell third and Apple and ASUS tied for the fourth spot.