Today I received an error while trying to browse an ASP.NET website application locally, “HTTP Error 503. The service is unavailable.”

Fortunately, I found an excellent post on troubleshooting IIS issues, Troubleshooting IIS7 503 “Service unavailable” errors with startup debugging by Mike Volodarsky. I am just documenting some of the things that were a little different for me. I am running Windows 7 and IIS 7. I downloaded Windows Software Development Kit (SDK) for Windows 8 from http://msdn.microsoft.com/en-US/windows/hardware/hh852363 and only installed the debugger to the default location. This made the path to the debugger executable  C:\Program Files (x86)\Windows Kits\8.0\Debuggers\x64\ntsd.exe. I used regedit to add the w3wp.exe Registry Key (HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\w3wp.exe) with the Debugger string value of C:\Program Files (x86)\Windows Kits\8.0\Debuggers\x64\ntsd.exe -server npipe:pipe=w3wp -g. I also added C:\Program Files (x86)\Windows Kits\8.0\Debuggers\x64\windbg.exe to my Path to make it easy to start in command line.

Unfortunately, I didn’t need to go through all of that. I never got the debugger to attach because the Worker Process wouldn’t start. After some experimenting I decided to change the Application Pool for my web application and the app came up. I looked at the old Application Pool and noticed something that didn’t hit me before. I spent 2 hours researching and poking around and my real error in this instance was the Application Pool I created for my web application was assigned to my local Windows account. When I was forced to update my password the password did not update on the Application Pool. So, updating the password fixed my issue. I have since created a new Windows account specifically for this web app that doesn’t have a password that expires.

Anyway, it was a nice exercise getting windbg up and running. Maybe I will really need it one day.

Fun Stuff!

*Safety Note: Use the Windows Debugger Install instructions above at your own risk. It may affect your Visual Studio Debugger.