Fixing Unknown Server Tag ‘asp:Silverlight’

When building Silverlight 2 projects in Visual Studio 2008 I found that I was getting errors on building the page:

Unknown Server Tag 'asp:Silverlight'

It turns out that I was getting the error because my project was on a network drive.  Once I moved the project to a local drive the error stopped happening.

Thank you to my colleague Marshall Agnew for that tip.

Comments (2)

  1. KiwiFreaK says:

    Try to add this:

    <%@ Register Assembly="System.Web.Silverlight" Namespace="System.Web.UI.SilverlightControls" TagPrefix="asp" %>

  2. Dave Myron says:

    You need to add a DLL to C:WindowsAssembly – then you should be able to have things build correctly even when hosted on a network drive.

    View the last comment at

    Good luck,


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