Microsoft is facing criticism from Chinese users about the way it is trying to persuade people to upgrade to its Windows 10 operating system.
Chinese microblog site Weibo said users had now made more than 1.2 million posts complaining about Windows 10.
The complaints in China follow criticism from IT experts who said Microsoft was using a "nasty trick" to make people upgrade.
Microsoft has not yet responded to the reports about Chinese complaints.
"The company has abused its dominant market position and broken the market order for fair play," Zhao Zhanling, a legal adviser for the Internet Society of China told the official Xinhua news agency.
He said by forcing the upgrade, Microsoft had not respected the users' right to choose what they install on their computers. This was important, he said, because eventually Microsoft might profit from the "unwanted" upgrades.
One Chinese man, Yang Shuo, who works at a Beijing-based PR firm, said the Windows 10 update interrupted him while he was working on a business plan. This meant he had to abandon the document which led to a meeting about a deal worth 3m yuan (£312,000) being cancelled.
The outcry on Weibo has led Microsoft to post information on the site to help people revert to older versions of Windows.
Earlier this week, Microsoft faced widespread criticism about changes it made to the pop-up box that regularly appears to encourage people using Windows 7 and 8 to upgrade.
The box was changed so that closing the pop-up by clicking on the "x" in its top- right corner was taken as permission for the scheduled upgrade to start. Typically, clicking an "x" stops a pop-up taking any further action.
The pop-up design change had been described as a "nasty trick" by some commentators.
The outcry over the change forced Microsoft to issue an update to give people another chance to cancel the Windows 10 installation.
Around 300 million devices have been updated to run the new system, according to figures from Microsoft, who said the free offer to install Windows 10 will end on 26 July.