Commented Issue: Error: AjaxControlToolkit requires ASP.NET Ajax 4.0 scripts. Ensure the correct version of the scripts are referenced. If you are using an ASP.NET ScriptManager, switch to the ToolkitScriptManager in AjaxControlToolkit.dll. [27267]

I've that error.

My page has

<%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit"%>

...
<asp:ToolkitScriptManager runat="server">
</asp:ToolkitScriptManager>
...
<asp:TextBox ID="ColorInsertTb" style="width:60px" runat="server" Text='' EnableViewState="false" />
<asp:ColorPickerExtender runat="server" ID="ColorInsertPickerExtender" TargetControlID="ColorInsertTb" SampleControlID="ColorInsertSample" />


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last package from nuget
VS2012, asp.net 4.5

what an hell: every time I try to start the toolkit on a new project I've a lot of this troubles....

Comments: I am getting the same error. I tried all solutions I found but not resolved yet. It seems that there is an issue in the latest release of AjaxToolKit (4.1.60919.0) when it works in ASP.NET 4.5.