Computer users have faced major technical issues with Microsoft's new Windows 10 software since its launch in July last year, according to research by U.K. consumer charity Which.
"We've received well over 1,000 complaints about Windows 10, as well as plenty of comments ... with PC users telling us that this software update has brought them nothing but problems," Andrew Laughlin, a senior researcher at the consumer association, said in a blogpost on Thursday.
Consumers in the U.K. have told the company about being "nagged" by Microsoft to install the operating system update and, despite declining advances, have experienced the Windows 10 software installing itself anyway.
Various problems, once it is installed, have included printers, wi-fi cards and speakers no longer working, as well as instances of lost files and email accounts no longer syncing, according to Which.
"In some cases, members' computers were so badly affected that they had to pay someone to repair it," Laughlin stated.
A spokesperson for Microsoft told CNBC via email that the Windows 10 upgrade is a "choice designed to help people take advantage of the most secure, and most productive version of Windows."
In June, Which surveyed 5,500 of its members, according to the BBC. The results showed that 12 percent of the 2,500 who had upgraded to Windows 10 had later reverted to an earlier version. Which has called on Microsoft to do better, adding that the tech giant is offering free support to anyone affected by Windows 10 upgrade.
"With more than 350 million monthly active devices now running Windows 10, the vast majority of customers who have upgraded to Windows 10 over the past year have had a seamless, positive experience," the Microsoft spokesperson told CNBC.
"For the relatively small number of users who may have issues with their upgrade experience, Microsoft offers a variety of options to get assistance including free customer support."