If you’ve locked down your machine permissions you may occasionally run into strange permission errors when developing on IIS. With all the hundreds of files that can be loaded, finding the source of the problem can be a nightmare.

One utility that I find very helpful for diagnosing problems, especially permission problems, is NT FileMon by Sysinternals. It can be obtained for free at [url]http://www.sysinternals.com/ntw2k/source/filemon.shtml[/url]

Using FileMon can be a little daunting. When you first run it, you’ll probably be surprised at how many files are opened and closed as you just perform normal activities on your machine. However, use the filter feature to look at just the application you want. IIS, for example, is “inetinfo” and you can filter records containing that only to see what IIS is doing. There is also the return flag indicating what the result of the file action was and you can look for those records that contain an error. This is a sure way to locate permission problems.

You’ll probably figure out quickly that this is a great tool for diagnosing all kinds of Windows problems.