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Update on svchost/msi performance issue and 3.0 Client distribution plan

Update on svchost/msi performance issue and 3.0 Client distribution plan

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Hi Folks

In addition to the next week’s  WSUS 3.0 release, we are making the new client portion available via the following plan to our customers who continue to experience performance issues like UI hang and long scan times.

 The new WUA client addresses these issues with deep architectural performance optimizations.  Combining the installation of the new client, with the latest MSI fix available in KB927891 available on Microsoft Download Center, will completely address the what we have fondly called the svchost/msi issue.  It’s important to keep in mind that the new client is only a partial solution and clients must have both KB927891 and the new 3.0 client installed for a full solution.

 On May 1st,  a standalone version of the client will also be made available to those of you who need to address this performance issue now.  Although this will be immediately available, it  will have to be independently distribute.   Instructions on how to get this standalone new 3.0 client version are available at -

 On  May 22nd. The following WSUS 3.0 full and client only updates will be available to WSUS:

Keep in mind that the new client is only a partial solution for the svchost/msi issue and clients must have both KB927891 and the new 3.0 client installed for a full solution. 

 ·         A critical update for WSUS 2.0 SP1 which contains the WSUS 3.0 client self update tree.  This critical update, applicable to WSUS 2.0 SP1 Server, if approved will install a new client self update versioned tree on the server.  When mapped clients check in with this updated WSUS 2.0 SP1 server, their clients will check their version against that installed on the server, see that they no longer have the latest version, and immediately self update to 3.0 versions.   The server will remain a 2.0 version with the capability to support the 3.0 clients.

  •  For SBS R2 WSUS 2.0 servers, another  critical update will be made available which will when approved, upgrade the R2 servers to WSUS 3.0.  Subsequent  to upgrade, the former 2.0 clients will self update to version 3.0. 
  • For all other servers running WSUS 2.0 (including SBS servers OTHER than R2) we will also be offering a WSUS 3.0 recommended update.   This update, when approved on servers running WSUS 2.0 will upgrade to 3.0, and as with the critical update, cause mapped clients at first check-in with the newly updated server, to self update to 3.0.
  •  For SBS non R2 customers, both of these updates will be available for your approval depending on the update scenario, and or client update path you wish to pursue. 

 We appreciate your patience while we pushed to make these architectural improvements to the client, and find a way to make them available in a variety of ways to suit your upgrade plans as well as your immediate needs.

Thank you the WSUS v3 team

 Update on 5/15: Based on the comments here, a follow-up entry blog entry has been posted @

Please refer to that post for clarifications on expectations after 3.0 client and KB927891 fixes are installed. Please use that post for more feedback.



  • Anyone know of a way that I can schedule when the wuauclt.exe runs?  

    Right now its 2 maybe three times a day.

    If I could minimise and predict the 100% CPU time, until the patch is fully complete, that would probably be bearable.

  • I have tested both of these updates on an XP Pro workstation in our WSUS 2.0 environment, but the problem persists.  Will it only solve the problem if the WSUS server is 3.0?

    This is very frustrating in our large 10,000 seat environment.  Please advise.

  • What about machines running Windows 2000?  KB927891 is for XP and higher, but the only machines I've seen have the svchost problem were running Win/2K.

  • So from reading the newsgroups:

    1) install the hotfix 927891

    2) install the WUA agent 3.0

    3) upgrade the Server to 3.0

    For the Hotfix: can that be applied to machines not affected? We aren't sure who's really affected as our user base is 3,000, and I'd like to push the hotfix via SMS to XP machines to make things simpler.  

    Any harm in doing that?

  • If I had my option - I would put 128Meg of in all of your machines and watch you all cry.

  • Jeff,

    WUS 3.0 server is not required for this fix on the client.

    Even with WSUS 3.0 client installed, you will still see high CPU usage when the scan happens.

    But with WSUS 3.0 client, the machine will be responsive and other applications can be launched and used.

    Please let us know what you are seeing in your environment.

    It may be better if you post the issue in WSUS newsgroup @

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  • We currently are using WSUS 2.0 to manage our 10,000 node distributed

    environment.  All workstation clients are Windows XP SP2.  We've been living

    with the 100% CPU utilization issue that occurs when clients perform update

    detection with the WSUS server(s).

    I was happy to read the article, "Update on svchost/msi performance issue

    and 3.0 Client distribution plan" on the WSUS 3.0 blog

    ( and was

    hopeful that it would resolve this issue, but the problem remains.

    I have a test machine where I first installed KB927891 and then updated the

    WSUS agent software using WindowsUpdateAgent20-x86.exe.  Both wuaueng.dll and

    wuauclt.exe are now version  I continue to see 100% CPU

    utilization for about 90 seconds after I run WUAUCLT /DETECTNOW, where

    SVCHOST.EXE runs between 65-98%.  During this time, the computer is


    I've been told by Sudheer [MSFT] that the fix does not require a WSUS 3.0

    back end to work properly.  He suggested posting my issue here.  Any advice

    please?  Why are we continuing to have this issue?

  • It works!  I had the wrong version of the WSUS Agent software installed.  Please read the thread at

  • I have tried both WindowsXP-KB927891-v3-x86 and WindowsUpdateAgent30-x86 and I don't think it is better.

    I am using WSUS 2.0 SP1.

    It looks like the problem is still there. Brutally slowing-down the PC.

    Isn't there a way to finaly fix it (after number of fixes for fixes which takes abou 3/4 year), please ?

  • Same here. Doesn't helped me a lot :(. Maybe because my primary AU client is MU not WU.

    I tried both patches on PCs that are connected to WSUS 2.0 SP1 and on PCs that are connected to main Microsoft servers. Still some older PCs (like celeron 1ghz with 512mb of ram) boots up and hangs for about 7-10 minutes. I can not open Word or any other applications during that period.

    Am I missing something?

    P.S. By the way i'm using Office 2003 Lithuanian edition. I noticed that some of the performance issues is because of this. In other words, the scan period is a lot smaller in the PCs without Office or with English versions.

  • У меня есть хорошая новость - эту проблему, скорее всего, устранит установка обновленной программы-агента

  • >>to experience performance issues like UI hang and long scan times.

    You call this a performance issue.  This issue renders the Microsoft Operating System USELESS.

    I cannot use my XP sp2 laptop at home because of this problem.

    Because this particular svchost loads multiple services in the same process killing this stops everthing else.

    If I don't kill it, I cannot do anything other than pressing the restart button. Because of this issue thousands of people are frustrated and productivity is lost and issues like this is going to push  windows users towards other operating systems

    >> will completely address the what we have fondly called the svchost/msi issue.

    Losing precious time and  hanging the OS is not a fond memory. whoever is responsible for this should be ashamed of  this.

    Software Update is supposed help alleviate problems. It must not get in the way of  the use of the operating system.

    Why this issue not caught by internal QA team makes one wonder about the quality of Microsoft.

    frustated user

  • I am in agreement with the last post.

    i work for a company supporting many small and medium businesses and in the last week we have recieved an inordinate number of calls for this issue, and god knows how many others are just living with this.

    whats more annoying is there is a working solution and it has not been widely publicised.

    Please just make this public knowledge, attach the notes about installing the latest update agent into the article for KB927891 as the searches in the MS knowledge base mention nothing of  this part of the fix

  • I hope MS will provide

    KB927891 and WU Agent 3.0 for  WSUS 2.0

    So than you could rollout these patches to clients with WSUS 2.0 first, next to update server to WSUS 3.0

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