How to permanently teach Visual Studio to detect my debugging information?

Question

Using Visual Studio 2012, maybe you've seen this message, too:

It says:

The following module was built either with optimizations enabled or without debug information:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\6dce49fa\6c454827\assembly\dl3\95d61873\9871ffdd_4288ce01\NoeDownloadbereichWeb.dll

To debug this module, change its project build configuration to Debug mode. To suppress this message, disable the 'Warn if no user code on launch' debugger option.

In the past I got this maybe once a week when starting to debug my ASP.NET application and resolved it by simply recompiling my solution.

Recently I switched to IIS Express this now happens every second/third time I want to debug my code after I did some changes.

I resolve it by one or all of the following steps:

• Rebuild my application (helps most of the time)
• Close IIS Express and rebuild my application
• Reboot Windows 8 and rebuild my application

I've found similar questions here and on Google and still am not able to permanently resolve this.

My question:

Can you imagine what causes this behaviour every now and then?

Update 1

The error seems to be related with/followed by ASP.NET error messages like (German):

Das Erstellen von "System.Net.Http.Extensions" oder das Erstellen einer Schattenkopie ist nicht möglich, wenn diese Datei bereits vorhanden ist.

Which rougly translates to English:

Cannot create/shadow copy "System.Net.Http.Extensions" when that file already exists.

(The refered file name "System.Net.Http.Extensions" is randomly changed by ASP.NET)

Update 2

I've switch back to Visual Studio Development Server and immediately got rid of the errors described above:

Don't know whether this is just on my system, or what's the reason for it.

Answer 1

Go to Tools > Options > Debugging > General > Enable Just My Code > Warn if no user code on launch