I just changed to Visual Studio Community 2015 and I'm having a weird issue running a project. The project builds without any errors. But, when I go to start debugging I get the following error:
There is an error in web.config. Please correct before proceeding. (You might rename the current web.config and add a new one.)
This only happens if web.config is not open in the editor in Visual Studio. If I open web.config in Visual Studio and try to run the project, I am able to do so and no errors are reported.
Has anyone suggested that we close and reopen Visual Studio?
I had the same problem in a Web API project in VS Enterprise 2015. I knew there was nothing wrong with the Web.config file because, like you, all I had to do was to have it open before hitting F5. It went away after I removed and re-added the project to the solution during solution re-organizing. You might want to try that. No logics here but then the error seems illogical too.
I fixed/stopped the issue above and wanted to communicate what my fix was with the exact same symptoms as above. I had switched to a different published environment when this started happening (from UAT to Dev) and I commented out a section in the web.config file. Double checked to make sure I commented out the exact text. I even cleaned my solution and rebuilt it, same problem. Strangely, I could publish to the dev environment and the application would run (Web app with IIS 7). The only difference between my local environment from when it was working and this problem was my web.config file. So I was thinking VS was having trouble accessing the file when not open in the IDE. I checked properties and the file had the appropriate settings. I then checked in the solution into our source code repository and the issue went away. We implement an SVN solution here. Hope this helps.