Search code examples
asp.netdebuggingvisual-studio-2010iis-7.5

VS2010 error: Unable to start debugging on the web server


I get error message "Unable to start debugging on the web server" in Visual Studio 2010. I clicked the Help button and followed the related suggestions without success.

This happens with a newly created local ASP.Net project when modified to use IIS instead of Cassini (which works for debugging). It prompts to set debug="true" in the web.config and then immediately pops up the error. Nothing shows up in the Event Viewer.

I am able to attach to w3wp to debug. It works but is not as convenient as F5.

I also have a similar problem with VS2008 on the same PC. Debugging used to work for both.

I have re-registered Framework 4 (aspnet_regiis -i). I ran the VS2010 repair (this is the RTM version). I am running on a Windows Server 2008 R2 x64 box.

I do have Resharper V5 installed.

There must be some configuration setting or registry value that survives the repair causing the problem.

I'd appreciate any ideas.


Solution

  • I got a new PC with Windows 7. I installed VS2010 and my development environment and hoped my F5 debug problem would be gone, but it still failed to start the debugger.

    This was a good clue since it ruled out the install of software.

    I finally traced it down to my HOSTS file. I had an entry for some of my local websites which I can access like "http://testsite.lcl" but the IP I had assigned was my machine's IP instead of using 127.0.0.1 so it looked like a remote server to VS2010. Changing back to 127.0.0.1 resolved the issue.

    Thanks for everyone's help on this.