The type or namespace name 'Windows' does not exist in the namespace 'System'


  • Hi,

    I have installed Microdoft Visual Studio codename "Orcas" and Microsoft Silverlight Tools Alpha for Visual Studio codename “Orcas” Beta 1  But, when i try to make my first Silverlight application, i received this error:

     Error 1 The type or namespace name 'Windows' does not exist in the namespace 'System' (are you missing an assembly reference?) C:\Documents and Settings\jvieira\My Documents\Visual Studio Codename Orcas\Projects\SilverlightProject1\SilverlightProject1\obj\Debug\Page.g.cs 11 14 SilverlightProject1

    How can i reference the System.ddl?


    • Moved by mbanavige Friday, June 01, 2007 10:21 PM Migration data
    Friday, June 01, 2007 12:27 PM

All replies

  • Check that you have also installed the Silverlight 1.1 Alpha. You need this version of the runtime to get the .net code support.

    Monday, June 04, 2007 1:37 PM
  • I am having the same problem. I have reinstalled VS 2008 RTM and SilverLight Alpha 1.1, even uninstalled framework but no luck.

    I made sure I have installed the SL Alpha 1.1 that is compatible with the VS2008 RTM. When I try to Add Reference in the SL project the window is blank, does not have the list of .Net namespaces.

    I am running XP SP2. Any guidance as to what I should do to make the SL project compiled will be greatly appreciated.


    Saturday, December 29, 2007 11:20 PM
  • Hi,

          Would you please try to create a brand new silverlight project, and do you see whether the default references made by the project template are listed in the solution explorer like, agclr, System.Core, etc...?

          In the add reference dialog, VS is supposed to load all the managed dll coming from the silverlight runtime folder such as /%Program files\Microsoft Silverlight%/. Currently, it looks like VS is not able to resolve the path to Silverlight runtime dll in your local machine.



                 Microsoft web developmenet tools team


    Thursday, January 03, 2008 2:21 PM
  •  I am getting the exact same problem. I just created a fresh Silverlight project and when I expand References I have an exclamation sign on agclr, system.silverlight and system.Xml.core.

    The other three references (mscorlib, system, and system.Core) appear to be fine. Double clicking on one of the bad references gives me "This project cannot be viewed in the object browser because it is unavailable or not yet built. Please ensure that the project is available and built."

    Wednesday, January 09, 2008 11:22 PM
  • Can you go to the Silverlight runtiem folder under "%Program Files%\Microsoft Silvelright" to check out whether "agclr.dll" is there?

    Also did you install the Silverlight runtime from

    Hope this helps.


                  Microsoft web development tools team

    Thursday, January 10, 2008 3:51 PM

    Thursday, March 06, 2008 4:04 AM
  • I am facing the same issue when I have installed Silverlight 3.

    I also couldn't locate agclr.dll in the "C:\Program Files\Microsoft Silverlight\3.0.40818.0" folder. Any solution?

    Sunday, October 04, 2009 6:35 AM
  • Can see the same yellow exclamation mark for "system.silverlight" and "system.Xml.core" in the references section.

    Any help will be appreciated.


    Sunday, October 04, 2009 6:38 AM