Earlier this week a server on the backend of the WGA service experienced a bug that resulted in a temporary outage. As a result, some systems were incorrectly flagged as being non-genuine, and we want to confirm for those who contacted us about this that it was indeed an error.  The WGA team apologizes for any disruption this may have caused for our customers.
The bug that caused this issue was identified and fixed within twenty four hours of being discovered. 

Here are the specific steps that can be taken now to fix this issue on any affected system that is genuine:

1)      Delete the data.dat file from C:\Documents and Settings\All Users\Application Data\Windows Genuine Advantage\data (The drive letter will depend on where the OS was installed)

2)      Revisit http://www.microsoft.com/genuine/downloads/validate.aspx to confirm whether the machine is genuine.

3)      Run wgatray.exe /b from the command line to ensure that the latest validation is updated for WGA Notifications.  This command may be absent from the user’s machine and should not be considered an error.  Please ensure that this is run as an Administrator.  A reboot may be required to remove all non-genuine notifications.

We also implemented a webpage with special instructions that will receive any traffic from systems that are running on product keys that could have been affected by this issue.

Also, systems that validated during this time and were given the incorrect answer may have cached that answer and could continue to use that locally cached value (of “not-genuine”) for up to 90 days for most systems or until the data.dat file is deleted.  Our routing of systems running on affected keys to a special webpage where steps can be found for fixing this issue will remain in place to help users of affected systems.