I've been receiving Windows validation error messages. In researching the problem, I ran across the info below, from social.microsoft.com/Forums. Not sure what to do about this...
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For the past few weeks, this forum has been seeing an increasing number of "non-genuine" notifications with the diagnostic reading of
Licensing Data-->
C:\Windows\system32\slmgr.vbs(291, 5) (null): 0xC004D401
In almost all cases, this has been caused by the installation of Avast v6. The only known solution is to uninstall Avast and run their removal tool, then validate the system again, then install an alternative Anti-Virus solution.
Avast appears to be in denial about the situation. They do not appear to be doing anything about it.