Entity-framework – find the console or debug output from code executed in the package manager window

I got annoyed by this recently too. I fixed it by putting a wrapper function in the Configuration class in the Seed method, and replaced calls to SaveChanges with calls to my function instead. This function would simply enumerate the errors within the EntityValidationErrors collection, and rethrow an exception where the Exception message lists the individual problems. This makes the output show up in the NuGet package manager console.

Code follows:

/// <summary>
/// Wrapper for SaveChanges adding the Validation Messages to the generated exception
/// </summary>
/// <param name="context">The context.</param>
private void SaveChanges(DbContext context) {
    try {
        context.SaveChanges();
    } catch (DbEntityValidationException ex) {
        StringBuilder sb = new StringBuilder();

        foreach (var failure in ex.EntityValidationErrors) {
            sb.AppendFormat("{0} failed validation\n", failure.Entry.Entity.GetType());
            foreach (var error in failure.ValidationErrors) {
                sb.AppendFormat("- {0} : {1}", error.PropertyName, error.ErrorMessage);
                sb.AppendLine();
            }
        }

        throw new DbEntityValidationException(
            "Entity Validation Failed - errors follow:\n" + 
            sb.ToString(), ex
        ); // Add the original exception as the innerException
    }
}

Just replace calls to context.SaveChanges() with SaveChanges(context) in your seed method.

I was able to resolve this error by installing PowerShell 3 via the Windows Management Framework 3 for Windows 7 SP 1 update (Windows6.1-KB2506143-x64.msu). It's unclear whether PowerShell 3 is required or the act of upgrading fixed whatever configuration issue caused this.