ASP.NET ‘Sys.Extended.UI’ is null or not an object error using AjaxControlToolkit

Posted on June 15, 2010

To resolve this issue simply add CombineScripts=”false” to the AjaxToolkitManager tag,

<asp:ToolkitScriptManager ID=”ToolkitScriptManager1″ runat=”server” CombineScripts=”false” ></asp:ToolkitScriptManager>

This entry was posted in .NET, IIS and tagged Ajax, AjaxControlToolkit, ASP.NET 3.5, VS2008.

14 thoughts on “ASP.NET ‘Sys.Extended.UI’ is null or not an object error using AjaxControlToolkit”

luisrgg said:
August 3, 2010 at 10:59 pm

thnks a lot !!!, very helpfull…

adriaanvanheerden said:
August 14, 2010 at 6:29 pm

After spending my entire Saterday reading 100’s of articles trying to fix this issue I was sure this easy fix wasnt going to work, but it did!!! Thanks a mil!!!!!

natrajme said:
August 26, 2010 at 10:22 am

Thanks a lot for this fix. I spend whole day searching for this kind of fix

jsk4125 said:
December 10, 2011 at 1:30 am

Hi, I know this is old, but I believe it’s
Thanks for the help, though. Can be a little difficult when it’s in one .ascx, and you can’t find the containing page’s ‘ScriptManager’ tag. (You can only have one or the other.)

jsk4125 said:
December 10, 2011 at 1:36 am

I’m an idiot. The ToolkitScriptmanager tag was right in the file that was blowing up. Sorry.

Khalil - Shreateh said:
May 18, 2012 at 7:35 am

spending all my f.day reading articles , and that was just it ? guys should publish it every where .

Non Sense said:
July 11, 2012 at 3:41 pm

YOU ARE THE MAN !!

Erling O. Vignisson (@erlingormar) said:
August 27, 2012 at 7:01 pm

Chiming in to say thanks – and hopefully get you up in Google’s search results by an inch or two 😉

Praveen Kumar Gandla said:
December 21, 2012 at 12:05 pm

Great buddy…. your solution awesome ….. thanks lot

sabiha khan said:
November 26, 2013 at 3:32 pm

I am also facing same issue but i am using ScriptManager,
please let me where should i have to add the CombineScripts property

Manikandan R said:
March 20, 2014 at 11:10 am

Thanks a lot.. You saved my day 🙂

Sarath potlacheruvu said:
July 30, 2014 at 6:08 pm

@sabiha khan you need to use ToolkitScriptManager not ScriptManager in your design page.Then right click for properties you will find CombineScripts property.

Chidananda n c said:
February 27, 2015 at 12:41 pm

CombineScripts=”false” This one solve my problem,,Thanks a lot..

Irfan Kumte said:
August 19, 2017 at 5:51 pm

God bless you bhai.:)

SYED IRTAZA ALI