Error after upgrade

I'm trying to upgrade to 2.6 from 2.5. I have run the sql query in the db and deleted all files in app_data and copy back settings and installedplugin. When I try to open my site I get this error:

"Value cannot be null.
Parameter name: instance
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: instance

Source Error:


Line 73:             UpdateContainer(x =>
Line 74:             {
Line 75:                 var registration = x.RegisterInstance(instance).Keyed(key, service).As(service).PerLifeStyle(lifeStyle);
Line 76:             });
Line 77:         }


Source File: G:\Webbplatser\Nop\Libraries\Nop.Core\Infrastructure\DependencyManagement\ContainerManager.cs    Line: 75
"