Updated

Microsoft said more than one million Internet users downloaded a test version of the new Windows 8 operating system in the first 24 hours of its release.

"One day later ... one million downloads of the consumer preview," the Building Windows 8 team announced late Thursday on its Twitter page.

Microsoft launched a test version of its next generation Windows operating system Wednesday at the Mobile World Congress in Barcelona. Steven Sinofsky, who heads the company's Windows division, said Microsoft made over 100,000 code changes to the operating system since the developer preview was launched in September 2011.

Windows 8, which supports ARM processors, is designed to position Microsoft in the fast-growing tablet market dominated by Apple's iPad and devices that run Google's Android software.

The system is not expected to be released commercially until late this year.

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Microsoft shares closed up 1.7 percent Thursday, hitting a 52-week high.