Could not load file or assembly 'System.Core, Version=


  • I created a web project in Orcas Beta based on the .NET 2.5 Framework a couple months ago.  Now, after I downloaded and installed VS 2008 beta, I'm getting a compile problem.


    In my web.config is:


    <compilation debug="false">


    <add assembly="System.Core, Version=, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>

    <add assembly="System.Web.Extensions, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

    <add assembly="System.Design, Version=, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/>

    <add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

    <add assembly="System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>

    <add assembly="System.Windows.Forms, Version=, Culture=neutral, PublicKeyToken=B77A5C561934E089"/></assemblies>



    The error I get during the build now in VS 2008 is:


    Error 4 C:\www\Projects\3.5\Elbalazo\Elbalazo35\Web\MasterPages\Sub.master: ASP.NET runtime error: Could not load file or assembly 'System.Core, Version=, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified. (C:\www\Projects\3.5\Elbalazo\Elbalazo35\Web\web.config line 38) C:\www\Projects\3.5\Elbalazo\Elbalazo35\Web\MasterPages\Sub.master 1 1 C:\...\Web\

    What should I do?


    Monday, September 17, 2007 2:57 AM

All replies

  • Figured it out.  I just added the System.Core.dll back into my Web Project (since it was for the updated .NET framework 3.5) and then in the web.config noticed that it added an entry for that automatically and then I just deleted the other outdated entry above.

    Monday, September 17, 2007 3:47 AM

    I have updated my old file from .net 1.0 & 2.0 to asp.net 3.5 using VS 2008 & getting the same issue.


    Any help?



    Thursday, October 11, 2007 5:03 PM
  • I have the same version of the framework, but I re-installed it, so am facing the same problem.

    How and where did you add System.Core.dll to the web project? I tried adding references and could not find it there.
    Saturday, October 20, 2007 12:43 AM