Only in Visual Studio 2015 : connection name 'DefaultConnection' was not found in the applications configuration or the connection string is empty

I am seeing the above mentioned error which is also asked about here and here.

I am only seeing this when I run my web project in Visual Studio 2015. If I open and run the project in VS2013, everything runs fine.

More details (I don't actually have a connection string named DefaultConnection in my web.config):

Line 125:    <membership defaultProvider="DefaultMembershipProvider">
Line 126:      <providers>
Line 127:        <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" />
Line 128:      </providers>
Line 129:    </membership>

Solution

So I managed to get this working, with the help of this post.

I also commented out the sessionState and membership tags (which had the references to the DefaultConnection) in my web.config - apparently I didn't need them.