Corey Roth [MVP]

I know not very many of you are using Vista to do your development work yet but I still highly recommend it for the simple fact that it allows you to have more than one web root now. Anyhow, If you have been working with Vista, you may have encountered the following error. "Unable to start debugging on the web server. An authentication error occurred while communicating with the web server. Please see Help for assistance." After searching through several blog posts, I finally found a solution that works, but it does make the site run in classic mode.

To resolve this, first make sure you have Windows Authentication installed in IIS (most likely you already do since you wouldn't have made it to this error likely in the first place). Next, go to your web site properties, click on Advanced Settings. Then click on your Application Pool and change the option to Classic ASP.NET AppPool. This should get you up and debugging in no time.

Also, if this error is not happening to you, as many other posts point out, be sure and run Visual Studio as an administrator (i.e. right click on icon and choose Run as Administrator).

Read the complete post at http://www.dotnettipoftheday.com/blog.aspx?id=353