Problem: I get an "access denied" error message when trying to save some change done to a web application in the IIS manager on Vista.

Possible solution:
Windows Vista comes with a new version of IIS. One of the new things in IIS 7 is that it saves it's configuration in the .net web.config files (previous versions used the "IIS metabase", which is a bunch of files internal to the IIS configuration tool). This is an improvement because it simplifies deployment and versioning - all you need to do is edit an xml file, whereas the IIS metabase is configurable only using a special API.

Correction(following Eyal's comment): actually the IIS metabase is an xml file that can be directly edited.

So, why the "access denied"? If you're making an application-level (as opposed to machine-level) configuration, many times it's because your application's web.config file is not checked-out for edit in VS, and so it is read-only on disk. IIS manager cannot write to it and shows you the error.

More on IIS 7 at pashabitz.com:
How to setup a custom HttpHandler in IIS 7
Developing ASP.NET apps under II7 on Vista.

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