Microsoft has been accused of not fully complying with the Chinese government's ongoing anti-monopoly investigation, despite saying in the past that it is willing to cooperate with the authorities.
The investigation has focused on compatibility and bundling issues with Microsoft's Windows and Office software, with the regulator now insisting on more information about the company's media player and web browser distribution.
Zhang Mao, the head of China's State Administration for Industry and Commerce (SAIC) said, "Information relating to Microsoft's suspected Windows and Office software has not been fully open."
The SAIC initially started investigating the tech giant following an industry complaint, but is yet to divulge any specific problems despite public raids of Microsoft's local offices last month.
According to reports carried out by StatCounter, Windows is still the dominant PC operating system in China, enjoying a 90 per cent share, with around 40 per cent of users sill using the officially-retired Windows XP system.
The Chinese government has recently made attempts to curb this dominance, such as by banning government purchases of Windows 8 devices, apparently due to security concerns.