Microsoft says the license for the public preview version of Windows 8.1 will end sometime in January 2014, after which the OS will no longer work when installed on a PC



From Neowin:

Microsoft released the free public preview version of Windows 8.1 in late June, during the first day of its BUID 2013 conference. In October, Microsoft released the commercial version of Windows 8.1, which was a free download for Windows 8 users and a paid upgrade for all other versions of the OS.

If for some reason you have installed the preview version of Windows 8.1 on one or more of your PCs, it's time to start thinking about upgrading to the final version. In a post this week on the Microsoft Small Business and Development blog, the company stated that the preview license will expire sometime in January 2014.

  Windows 8.1 Preview license ends in January 2014