You have Microsoft Office 2010 or a later version installed on a computer that is running Windows 8.
Windows 8 was activated by using KMS activation in your corporate network.
The computer is disconnected from the corporate network.
In this scenario, you unexpectedly receive a notification that says the Windows is not activated. Additionally, you are prompted to activate Windows.
This issue occurs because the KMS activation is not renewed correctly. In a managed environment, a KMS computer is reactivated every 7 days. When a computer is disconnected from a corporate network, there should be 173 to 180 days remaining before you have to reactivate Windows. If a computer is not reactivated correctly, you have an indeterminate time between 1 and 180 days remaining to reactive. Therefore the computer can be deactivated unexpectedly.
Cumulative Update information
To resolve this issue, install the Windows 8 and Windows Server 2012 cumulative update 2822241. For more information about how to obtain this cumulative update package, click the following article number to view the article in the Microsoft Knowledge Base:
2822241 Windows 8 and Windows Server 2012 cumulative update: April 2013
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