ASP.NET UpdatePanel Time Out

In my case the ScriptManager object was created in a Master Page file that was then shared with the Content Page files. So to change the ScriptManager.AsyncPostBackTimeout property in the Content Page, I had to access the object in the Content Page's aspx.cs file:

protected void Page_Load(object sender, EventArgs e)
{
     . . . 
     ScriptManager _scriptMan = ScriptManager.GetCurrent(this);
     _scriptMan.AsyncPostBackTimeout = 36000;
}

This did the trick (basically just ignoring all timeouts):

<script type="text/javascript"> 
        Sys.WebForms.PageRequestManager.getInstance().add_endRequest(function (sender, args) { 
            if (args.get_error() && args.get_error().name === 'Sys.WebForms.PageRequestManagerTimeoutException') { 
                            args.set_errorHandled(true); 
            } 
        }); 
    </script> 

There is a property on the ScriptManager which allows you to set the time-out in seconds. The default value is 90 seconds.

AsyncPostBackTimeout="300"

Please follow the steps below:

Step 1: In web.config, set httpRuntime maxRequestLength="1024000" executionTimeout="999999"

Step 2: Add the following setting to your web page's ScriptManager: AsyncPostBackTimeout ="360000"

This will solve your problem.