Silverlight Runtime Install Failure in VS2010 RC

If you have the latest version of the Silverlight end user runtime installed, you may see the following error after installing Visual Studio 2010 RC:


[02/10/10,18:18:55] Microsoft Silverlight: [2] Error code 1502 for this component means "The event log file is full.
[02/10/10,18:18:55] Microsoft Silverlight: [2] Component Microsoft Silverlight returned an unexpected value.
[02/10/10,18:18:55] Microsoft Silverlight: [2] Return from system messaging: The event log file is full.



There are two versions of the Silverlight runtime: The end user runtime and the developer runtime which contains a managed debugging component that allows developers to debug their Silverlight applications.

Silverlight recently released an update on Microsoft Update to the runtime to support features you’ll see on the web broadcast of the Winter Olympic Games.  Updates were released for both the end user and developer runtimes.

Visual Studio 2010 RC has a slightly older release of the dev runtime included.  If only the end user runtime is installed, during VS installation, it detects that the managed debugging component is missing and attempts to install the dev runtime.  However, because the newest end user runtime is already installed, installation fails.  (And the error code is misinterpreted to mean that the event log is full.


This issue was recently fixed, but after the final build of VS2010 RC was released, so it will be in the RTM release.  In the meantime…

If you’re not a Silverlight developer, go ahead and ignore this message.  Your installation of Visual Studio is not affected.

If you are a Silverlight Developer, you can download and install the latest version of Silverlight 3 Developer Runtime or the Silverlight 4 Beta Developer Runtime so that you can debug your Silverlight projects.

Comments (15)
  1. I had the same issue and could fix it by installing the Silverlight 3 Developer Runtime. I am not sure about Silverlight 4 Beta, since every MS writes that we have to wait for the next drop. So is this the next drop ? 😉

  2. Amy Dullard says:

    The links above are for the Silverlight developer runtime.  Right now, the Silverlight 4 Tools for VS2010 RC are not publically available.

  3. Peter Gfader says:


    I installed VS2010RC 5 days ago, but I cant get the debugging for Silverlight working…

    The error I get is:

    Microsoft Visual Studio

    Unable to start debugging. The Silverlight Developer Runtime is not installed. Please install a matching version.

    I uninstalled all Silverlight SDK’s, Tools and runtimes in Control panel.

    And then installed your link Silverlight 3 Developer Runtime

    I have now installed:

    • SDK version 3.0.40818.0
    • runtime 3.0.50106.0

    but still get that error message

    Silverlight debugging in VS2008 was working before…

  4. Marc Roussel says:

    I have SL 4 beta developer runtime, I have vs 2010 beta 2 and I’m developing a SL 3 app which needs to be contantly updated and publicly available.

    Now can I use the VS 2010 RC with all this in mind ?

  5. Amy Dullard says:

    @Roussel yes, you can build SL3 apps with VS2010 RC and the Silverlight 4 Beta developer runtime

  6. Amy Dullard says:

    @Peter look it your registry for the value of


    if that isn’t set, then you don’t have the developer runtime installed

  7. pete.d says:

    NOTE: installing VS2010 Pro RC, an error was reported installing Silverlight.  However, it was NOT the "event log full" error.  Instead, I actually got a crash (with the "check online for solution" alert), and the VS2010 installer simply reported that it failed to install.

    Is this still the same error as the known problem being reported here?

  8. James Sun says:

    Thanks for the tip about the Silverlight Developer runtime.  After I installed v3, VS2010 worked great!

  9. Amy Dullard says:

    @pete.d No, the crash is a separate issue related to Handwriting Recognition that is currently being worked on

  10. Lasse Christiansen says:

    Thanks for the note – I have just experienced the same problem.. I’m glad that it does not affect the entire MS VS 2010 solution.

  11. DC says:

    I installed the SL3 developer’s runtime, and i can debug my SL projects in VS2008 without a problem. But then I go visit a website with SL clips on it which requires a SL end-user runtime installation.  But it can not be installed because it keeps saying the my SL has already been installed.  What shall I do now?  Can’t I ever watch any SL clips while browsing the internet ever again for being an SL developer without constantly uninstalling and reinstalling these two versions of SL run-times ?  That’s insane!!

  12. Amy Dullard says:

    The developer runtime has all the same bits as the end user runtime and it also include the debugging component.  So, you do not need to uninstall it to view SL apps on the internet.

    However, you DO need to make sure when it is upgraded, that you are choosing the developer installer (Silverlight_Developer.exe).

    The Silverlight is updated via Microsoft Update.  So when a new version is released, it will update your developer runtime to the lastest developer runtime.

    If you choose NOT to use Microsoft Update…OR, you are visiting a site that is demo-ing an application built with a beta version of Silverlight, you will need to manually install the latest version.  The installer for the developer runtime can be found on under the "Get Started" tab.  Or, you can use the links in the blog above.

  13. Thanks Amy, that helps.


  14. _Joey_Abra says:

    Thank you very much

    You don't know what kind of problems I had. I was on  the  verge  of  reinstalling Visual Studio 2010 ^^

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