There is a workaround manual rule posted here that has worked well for us~

Deb
UMW

-----Original Message-----
From: Cisco Clean Access Users and Administrators [mailto:[log in to unmask]] On Behalf Of Greg Fuller
Sent: Wednesday, January 26, 2011 11:24 AM
To: [log in to unmask]
Subject: Re: Microsoft Security Essentials 2.0

We just got bit by this too.....after students just moved back in on 
Sunday.  :(  That's what we get for not keeping up with the mailing list 
for a few months!  We typically install MSE for those clients that we 
can't get their prefered AV to function properly, or our campus licensed 
Sophos install to function right either.  

Anyway we found that if you use the old MSE v1.x installer it WILL NOT 
auto-uggrade to MSE v2.x through Windows Updates/Microsoft Update.  New 
definition files still function with the old MSE v1.x until an updated NAC 
Agent is available that detects v2.x.  

--greg


Gregory A. Fuller - CCNA
Network Manager
State University of New York at Oswego
Phone: (315) 312-5750
http://www.oswego.edu/~gfuller