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kb 2871389
About this tag
KB 2871389 is a prerequisite update for Windows 8 and Windows RT users who want to upgrade to Windows 8.1 via the Store. Without this update, the Windows 8.1 upgrade may not appear as available in the Store. The update is delivered automatically through Windows Update if automatic updates are enabled, but users who have turned off automatic updates may need to install it manually. This update resolves issues that prevent the Store from offering the Windows 8.1 upgrade. It is available for both x86 and x64-based systems. If you are having trouble finding the Windows 8.1 update in the Store, installing KB 2871389 is the recommended first step.
Some Windows 8 and RT users may need an update before 8.1 can be found via the store. Luckily Microsoft have a blog released so users know what to look for:
Reference:
http://windows.microsoft.com/en-us/windows-8/why-can-t-find-update-store
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