Auto-attach to process aspnet_wp.exe on machine failed
An additional tip to the 'Things to Check' that Microsoft lists in 'Unable to Start Debugging on the Web Server' when start debug fails from Visual Studio is to check wether or not the ASP.NET version for the current application catalog is set to the same as the project. As default new virtual paths always gets the highest version assigned which will prevent, for instance, Visual Studio 2003 to debug projects on a machine that has ASP.NET version 2.0 installed.
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