Update packaging changes…

Hey folks,

Just a heads up that the way in which the FCS definition updates are packaged is being revised. We wanted to announce that the antimalware definitions team has released a set of improvements that will drastically reduce both the size of the definition downloads for:

  • Microsoft Update to WSUS
  • WSUS Upstream Server to WSUS Downstream Server

and the network utilization during those transfers.  

We will be releasing an update to Microsoft Knowledge Base article 977939 in the near future that details the specifics with regards to the change, but we wanted to make you are aware that this is already in place and working properly.  

The short description is that we are no longer downloading the full base set of definitions and engine with each download to WSUS.  Instead, there is a monthly base package that is downloaded and then deltas that revolve around that monthly base are downloaded by the WSUS server for each definition release.  The result of this is that instead of seeing hundreds of megabytes per day downloaded by WSUS, the downloads should instead be in the low tens of megabytes.  For those with WSUS servers on slower WAN links or for those with restricted bandwidth on internet connections, this is much needed relief in regards to our definition distribution mechanism. 

Thanks -

Kurt Falde, Microsoft Forefront Support Escalation Engineer

Comments (7)
  1. Hi Andy,

    There have not been any changes that would cause defintions to have CRC errors – can you open a support case? There may be something that needs investigation:


    Alternatively, you can try posting this question on the Forefront Client Security General TechNet forum:



  2. Matto says:

    Great news guys – that's an excellent result! This will be very much appreciated by our users at sites with wireless links.


    Matto 🙂

  3. Jordi Bargallo says:

    Hi, I will sure appreciate this new reduced policy of distributions, very cool! I've noticed on clients and also on windows catalog that on Jun/8th there's only one definition published and no new ones since then. Has this change anything to do with it? Usually you use to publish 3 per day, right? Any problems on your publishing systems?

    Regards from an update-maniac 😉

  4. G.Vitaly says:


    1) How can I find the expiration date of Microsoft Forefront Client Security demo version?

    2) What functional limits can be constrain on the sever and the users after the expiration date expires?


  5. Hi Jordi – what you saw was a transient issue… it should be resolved now.

    G.Vitaly – there should be an event from MOM in your Event Log – this event will contain the expiration date… After the evaluation version of FCS expires, the database will no longer accept client data, and the FCS console will not display.

  6. Andy Heywood says:

    As of 16th June our 2 WSUS servers have been unable to download FCS definitions(all other updates are fine) and keep reporting CRC verification failure on the files when they attempt the definition download.  I am just wondering if anyone else has experienced this issue?

  7. Andy Heywood says:

    Thanks for that kimborly – I have opened a support case

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