The type 'System.Web.UI.ScriptManager' is ambiguous: it could come from assembly

Question

When I run my asp.net app I get the error

The type ‘System.Web.UI.ScriptManager’ is ambiguous:

I am having the same problem this person is having http://forums.asp.net/t/1313257.aspx , when I change the 1.0.61025.0 to 3.5 and re-compile It resets it to 1.0.61025.0

what I can I do to resolve this. I've been trying to get my app running for hours now.

Thanks

Edit ~ HELPPpppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppppp

I see 2 system.web.extensions in the GAC. I tried to remove with gacutil.exe /u system.web.ext ensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35 Microsoft (R) .NET Global Assembly Cache Utility. Version 2.0.50727.42 Copyright (c) Microsoft Corporation. All rights reserved.

Unknown option: Version=1.0.61025.0 what am I doing wrong.

Edit ~ MY SOLUTION

I went to "Add Remove Programs" and un-installed the Ajax Web Extensions 2.0 version 1.0.61025.0

Answer 1

It looks like you are (perhaps indirectly) referencing the old System.Web.Extensions DLL. Check your config file and search your application for "System.Web.Extensions". Also make sure the old version is not in your bin folder (and does not get copied there).

Make sure you are not using any other libraries that use the old System.Web.Extensions DLL, ie the AJAX Toolit 1.0.x.

Answer 2

Update your project reference and clean out your bin directory. Asp.net is loading the previous version of AJAX from bin

Make sure you remove: - System.Web.Extensions.dll - System.Web.Extensions.Design.dll
- old versions of AjaxToolkit.dll

Answer 3

A newer alternative to solve this is to add this to the web config