Assume you have a computer that is running Windows 8.1, Windows RT 8.1, or Windows Server 2012 R2. The touchpad becomes disabled on the logon screen.
Note To work around this issue, plug in or unplug a mouse from the computer.
To resolve this issue, 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