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VS 2005 Debugging Issue with AJAX Applications on IIS7 on Vista

I wanted to play around with AJAX and hence downloaded the Extensions and the ToolKit. I created a new ASP.NET AJAX Enabled Web Site and after adding the Update Panel to update a label control, I hit F5. Surprisingly, I got an error when trying to debug.

This was easy to fix and happens for all web sites built using VS 2005 that you try to debug on IIS7. The site should have Windows Authentication enabled. I did that change and tried to debug again but still got an error as authentication error. There is description of a related hotfix here. However I was working on Vista Ultimate so wasn't sure if this hotfix will work for me or not.

For some other work, I had altered the DefaultAppPool setting for applications and I decided to give it a try as well. Steps to alter the application pool

  1. In IIS7 Admin Console, click on the site in question
  2. In the right side "Action" panel, click on "Advanced Settings"
  3. In the dialog that comes up, change the Application Pool from "DefaultAppPool" to "Classic .NET App Pool"

With these changes, I was able to debug the ASP.NET AJAX application without having to install any hotfix.

Surprisingly, a little later, when I changed the Application pool back to "DefaultAppPool", I was still able to debug without any authentication errors again !


I had other issues with Vista SP1, VS 2005 and IIS 7 and I have written a post here

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