Hi guys,

I just tried booting up Umbraco 8 from dev-v8 this morning.
After running all clean*.bat files and removing binaries and configs, I get the following exception:

Value cannot be null.
Parameter name: connectionString 
  Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

 Exception Details: System.ArgumentNullException: Value cannot be null.
Parameter name: connectionString

Source Error: 

Line 103:           //Mandate.That(myParam != null,
Line 104:           //     textManager => new ArgumentNullException(textManager.Get("blah", new {User = "blah"})));
Line 105:       }
Line 106:   }
Line 107:}

 Source File:  C:\Users\bi-lea\Source\Repos\OpenSource\Umbraco-CMS\src\Umbraco.Core\Mandate.cs    Line:  105 

Stack Trace: 

[ArgumentNullException: Value cannot be null.
Parameter name: connectionString]
   Umbraco.Core.Mandate.That(Boolean condition, Func`1 defer) in C:\Users\bi-lea\Source\Repos\OpenSource\Umbraco-CMS\src\Umbraco.Core\Mandate.cs:105
   Umbraco.Core.Mandate.ParameterNotNullOrEmpty(String value, String paramName) in C:\Users\bi-lea\Source\Repos\OpenSource\Umbraco-CMS\src\Umbraco.Core\Mandate.cs:33
   Umbraco.Core.Persistence.DefaultDatabaseFactory.Configure(String connectionString, String providerName) in C:\Users\bi-lea\Source\Repos\OpenSource\Umbraco-CMS\src\Umbraco.Core\Persistence\DefaultDatabaseFactory.cs:151

Adding a connection string to web.config makes it redirect to the installer, but it says nothing and the white spinner just spins and spins.

Hints appreciated. :)

Lars-Erik