Global PC shipments plunged in their worst decline in nearly two years last quarter, according to analyst houses Gartner and IDC.
Gartner counted a 9.5 per cent year-on-year fall in shipments to 68.4 million units in the second quarter of 2015.
IDC, which doesn't include tablets in its own calculations, recorded a year-on-year drop of 11.8 per cent, to hit 66.1 million units sold.
Both firms partly blamed Microsoft's forthcoming operating system, Windows 10, saying sellers have already much reduced their inventory ahead of its 29 July launch.
Mikako Kitagawa, principal analyst at Gartner, said: "The Windows 10 launch scheduled for the third quarter of 2015 has created self-regulated inventory control. PC vendors and the channels tried clearing inventory as much as possible before the Windows 10 launch."
Other factors included a price hike announced by US vendors in various regions to make up for strong growth in the US dollar, as well as a lack of catalysts to push people to buy new PCs after the expiration of Windows XP.
In EMEA, IDC warned that weakening demand and high existing inventory levels also harmed sales.
Loren Loverde, VP of worldwide PC trackers and forecasting at IDC, added: "We continue to expect low to mid-single digit declines in volume during the second half of the year with volume stabilizing in future years."
ColleagueRajani Singh, senior PC research analyst, said 2015 would experience a "healthy second half" as purchases pick up following Windows 10's launch.
But Loverde claimed the new OSwould not provide the sales boost vendors might hope for, due to Microsoft's policy of free upgrades.
"We're expecting the Windows 10 launch to go relatively well, though many users will opt for a free OS upgrade rather than buying a new PC," he said.
"Competition from two-in-one devices and phones remains an issue, but the economic environment has had a larger impact lately, and that should stabilize or improve going forward."
