The taskbar does not work correctly on a computer that is running Windows Server 2012 R2, Windows 8.1, or Windows RT 8.1. In some cases, the taskbar remains on the screen for longer than you expect or there may be a duplicate taskbar.
To resolve this problem, install update rollup 2984006. For more information about how to obtain this update rollup package, click the following article number to view the article in the Microsoft Knowledge Base:
2984006 September 2014 update rollup for Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates
Article ID: 2995004 - Last Review: 3 Nov 2014 - Revision: 1
Windows Server 2012 R2 Datacenter, Windows Server 2012 R2 Standard, Windows Server 2012 R2 Essentials, Windows Server 2012 R2 Foundation, Windows 8.1 Enterprise, Windows 8.1 Pro, Windows 8.1, Windows RT 8.1