Fixing WebForms.PageRequestManagerServerErrorException Status code 500

Here's a fix for the error WebForms.PageRequestManagerServerErrorException Status code 500.
I modified the MasterPage's ScriptManager as follows:

                    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="false">
                    </asp:ScriptManager>

UPDATE: This might fix the error, but it limits the functionality by not allowing Partial Page Rendering. This may not be acceptable. Here is a hint to avoid breaking the AJAX:

Hint: Be careful when changing Control names. The IDE won't catch the name change in the Extenders section of the TargetControlID.