Even so, Microsoft made it clear that it considered the practice outside legality's bounds. "Windows 10, whether you get it on 7/29 or whether you got it in a preview form through the Windows Insider Program, is intended to be installed on [a] Genuine Windows device," said Gabriel Aul, engineering general manager for Microsoft's operating system, in a June 22 blog.
People who have Insider installed without an underlying linked license to Windows 7 or 8.1 should be especially interested in maintaining the OS for their testing: Once they drop off the preview program, they may reinstall Windows 10 and shift to Insider, but as RajithR said, the copy will not be activated.
Users can check the Insider build's expiration date on their device by typing winver.exe in the Windows 10 search bar. For example, the latest preview, build 10565, which was released Monday, expires on July 16, 2016.
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