Entity Framework: Add-Migration fails with Unable to update database

I have been using Entity Framework (5.0) for a while now in a project (ASP.NET MVC in VS2012 Express). Right now, though, I am no longer able to add migrations.

PM > Add-Migration -projectName MyProject.DAL TestMigration
Unable to update database to match the current model because there are pending changes and automatic migration is disabled. Either write the pending model changes to a code-based migration or enable automatic migration. Set DbMigrationsConfiguration.AutomaticMigrationsEnabled to true to enable automatic migration.

I do not know if this gives any clue but the 'Unable to ..." text is displayed in red.

I have tried to enable automatic migration (which makes no sense as I am trying to write the pending model changes to a code-based migration) and that results in the required migration in the database. However this is not what I want because I then I do not have a migration in the project.

I have tried to remove the database and recreate the database. The database is recreated (up to the previous migration) but when I then try to use the Add-Migration I still get the "Unable to update.." error.

Edit

I tried the -force parameter but with no difference.

The contents of my configuration class (I did not change anything after the previous migration):

    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
    }

    protected override void Seed(Bekosense.DAL.Context.BekosenseContext context)
    {           
        context.Database.ExecuteSqlCommand(Properties.Resources.TriggerAlertMessageDrop);
        context.Database.ExecuteSqlCommand(Properties.Resources.TriggerAlertMessageCreate); 
        context.Database.ExecuteSqlCommand(Properties.Resources.TriggerAlertMessageSentDrop);
        context.Database.ExecuteSqlCommand(Properties.Resources.TriggerAlertMessageSentCreate); 
        context.Database.ExecuteSqlCommand(Properties.Resources.AddDbUsers);
    }

Edit 2 I found out that I am able to do an add-migration when I comment the following line out in my DbContext:

//Database.SetInitializer(new MigrateDatabaseToLatestVersion<MyContext, Configuration>());

when I leave the line above active and comment out everything in the Configuration file, it still won't work. Why is the Database.SetInitializer line causing this strange behaviour?