I’ve been doing some work with ASP.NET MVC but was having periodic issues with Visual Studio 2008 hanging (freezing / becoming unresponsive) when I tried to run my web application with debugging.  The problem only occurred with a specific web project.

I tried deleting the Temporary ASP.NET Files (%userprofile%\AppData\Local\Temp\Temporary ASP.NET Files) but that did not solve the problem.

I tried deleting the obj folder.  No luck.

I tried waiting it out one evening.  I eventually feel asleep and when I awoke sometime in the middle of the night, my web app was happily waiting for input and Visual Studio debugging was completely responsive.  That proved to be a temporary salve.

showallfiles The problem resurfaced again a few days later and I finally figured out the problem with my uncooperative debugger.  I have a folder containing approximately 20,000 images that are not included in the Visual Studio web project but are sitting in a directory in the web site.  I had turned on "Show All Files" in Solution Explorer to add some script files into the project.  When "Show All Files" is off, F5 (Start Debugging) works like  champ.  When "Show All Files" is on, Visual Studio becomes unresponsive.  In reality it is not "frozen" but simply taking a very long time to process those 20,000 image files.

Mystery solved.