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Roll-up update KB 2775511. Report of data truncation when utilized with SMB 2.0 connections for multiple data read and writes to network share (New update has released KB 2732673)

Roll-up update KB 2775511. Report of data truncation when utilized with SMB 2.0 connections for multiple data read and writes to network share (New update has released KB 2732673)

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UPDATE: The update for the issue documented here has released as of 8/13/2013.  The update is available under KB article 2732673


For those who have installed the prior 2775511 update already, the update released under KB 2732673 should be installed after the 2775511 update.






Writing today to provide a support update to the community on an issue that we are seeing in developer support on an optional Windows update. Specifically, we have a report were data is being truncated from an application utilizing network shares from a client Windows 7 that making requests for data storage to a Windows Vista, Windows 7, Windows Server 2008/2008 R2, or Windows 2012 machine.


The report is that data truncation issue occurs only after installation of optional update under KB 2775511 on Windows 7 SP1 client machines. To date, this is the report that we have on the issue. We are working closely with the reporting customer to resolve the report with progress being provided by the customer here:


In addition, we have reports that the following additional two updates can cause the data truncation issue under the same scenario:


The specific component has been identified to be in the RDBSS.SYS component. The updated RDBSS.SYS component has to be on the client machine only for the issue reported. In addition, the remote machine has to be able to support SMB 2.0 communication in order for the issue to surface.


For more background on these Microsoft updates, the above updates are released as hotfix releases to address specific issues. The KB 2775511 update is an cumulative hotfix update that is exclusively available via the site. By being available only through the windows update catalog, the KB 2775511 update is not considered a security update and is not being deployed broadly.  


In terms of workarounds, the following options are potential options while further investigation continues between Microsoft and the reporting customer:


  •  Not installing the KB 2775511 update and updates since release of the KB 2775511 update that has a newer RDBSS.sys component (KB 2732673, KB 2824408)
  •  Hosting the remote data on a machine running a lower version of SMB such as Windows 2003
  •  Disabling SMB 2.0 on the remote machine hosting the data being truncated.   Please note this is not recommended unless absolutely necessary as detailed in the following article by Microsoft on disabling SMB 2.0:




UPDATE: The hotfix is currently still under development with the update being in testing.  The update is on track to be released within the next 60 days (August 2013).  

UPDATE: The update for the issue documented here has released.   The update is available as of today at under KB article 2732673:




  • We also experienced issues with this Hotfix 2775511 and the application Endnote 4.0.2. Symptoms were crashing application resulting in corrupt library data files. Removal of the hotfix resolved the problem. If the Endnote data files were stored on a local drive the problems did not occur.

  • @RCRNZ, can you send over where you received Endnote 4.0.2  (vendor & location)?  We will investigate here further.

  • In our 2008R2 Citrix terminal server farm I often see these crashes since KB2775511 has been applied:























    Beside the data corruption bug in this version of rdbss.sys, possibly there's a crash issue too.


  • @Daniel:  Thank you for the feedback.   The stack below is under investigation as of today now.

    At this time for the stack below, we would advise to uninstall the 2775511 update on the servers in question.   More information will be forthcoming on resolution.



  • Is this fix still being released next month? If so when will this be available? The 1 August for us is tomorrow so curious as to when we could get a working update. Thanks.

  • @Kevin.  Thanks for the note on status.  We did a check today earlier on status with the release.  So far, so good on a release mid-August.  I will have an update here in two weeks on the release.


  • And today two weeks has passed. Any news about the fix? :-)

  • @Sandra, fix should be live this week.  Will post here once it is public

  • The update for the issue documented here has released.   The update is available as of today at under KB article 273673:  

  • Great, so we have a hotfix.  Does this need to be installed on the servers, the clients, or both, to resolve this issue?  Will the hotfix be put into the Microsoft update catalog so we can deploy it via WSUS, the way we deployed KB2775511?

  • @Althornin, for the hotfix, it should be installed after the 275511 update on all machines that have 275511 update installed.  

    The hotfix is not in the WSUS catalog

  • @Nathan

    I know the hotfix isn't currently in the catalog - I asked if it will be placed in the catalog (at some point).  Otherwise, deployment of this hotfix is going to be much harder than deploying KB2775511 was.  I'm just asking that you consider it...

  • @Althornin, it is not int the catalog with no plans to be in the catalog. I have passed the feedback along.

  • It would be great if this could be added to the catalog. Especially considering that KB2775511 was such a substantial update and this is a fix for that update.

  • There are two hotfixes listed for each platform.  I think this is incorrect.

    For example, you can download Windows6.1-KB2732673-v3-x64.msu as well as Windows6.1-KB2732673-v4-x64.msu.  

    Do we need to install both or only V4?

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