VS2010 error: Unable to start debugging on the web server

asp.net, debugging, iis-7.5, visual-studio-2010

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.

Problem

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.

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