Microsoft Anti-Monopoly Investigation Opened by Chinese Regulators

China's State Administration for Industry & Commerce (SAIC) is conducting an anti-monopoly investigation into Microsoft Corp over its Windows operating system. The investigation is just the latest in a growing number of probes that have unnerved Western firms located in China.

China's SAIC is also investigating a Microsoft vice president and senior managers, and has made copies of the company's financial contracts and statements, the agency said, according to Reuters.

Microsoft, which has struggled to make inroads in China thanks to rampant piracy, failed to fully disclose information about Windows and its Office software.

The investigation comes as U.S.-China business relations have been strained due to disputes over data privacy.

Investigators raided Microsoft offices in Beijing, Shanghai, Guangzhou and Chengdu on July 29, according to Reuters.

The SAIC obtained documents, e-mails, and other data from Microsoft's servers and computers, but they were not able to finish the investigation as Microsoft had said some of its key personnel were not in China.

Microsoft had been suspected of violating China's anti-monopoly law since June 2013 in relation to issues with bundling, compatibility, and document authentication, according to Reuters.

Microsoft said it had been visited by officials and that they are "happy to answer the government's questions" in a statement released after the announcement from the regulator.

Back in May, central government officers were told not to install Windows 8, which is Microsoft's latest operating system, on its new computers.

The ban has not been lifted since, as more than one procurement notices since then have now allowed the OS.

It is still unclear how Microsoft violated China's anti-monopoly law, said Duncan Clark, chairman of Beijing-based tech consultancy BDA.

"It's ironic they can be accused of a monopoly in a mostly pirated operating system market, as they were criticized for ending support to mostly non-paid versions of Windows XP," said Clark, according to Reuters.