Hey Richard,

i think a very similar problem appears with Vorto package 1.2 and SEOChecker.

Especially when you try to call the vorto extension on a IPublishedContent.. GetVortoValue()..

I first thought it was a vorto issue and already created a issue with Matt from Vorto.

What i then did, was added the vorto project and debugged it.

it broke on this method in vorto:

private static PublishedPropertyType CreateDummyPropertyType(int dataTypeId, string propertyEditorAlias)
    {
        return new PublishedPropertyType(null,
            new PropertyType(new DataTypeDefinition(-1, propertyEditorAlias)
            {
                Id = dataTypeId
            }));
    }

But the problem was in the contructor of PublishedPropertyType in the core of umbraco and especially in the InitializeConverters() method.

So i went further and added the Umbraco.Core project from 7.1.4 to my solution and debugged further.

And then I saw that it broke on the method IsConverterFor on the {SEOChecker.MVC.PropertyEditorConverters.SEOCheckerMetadataConverter}

  IEnumerable<IPropertyValueConverter> GetCompatConverters()
    {
        var propertyEditorGuid = LegacyPropertyEditorIdToAliasConverter.GetLegacyIdFromAlias(PropertyEditorAlias, LegacyPropertyEditorIdToAliasConverter.NotFoundLegacyIdResponseBehavior.ReturnNull);
        return PropertyEditorValueConvertersResolver.HasCurrent && propertyEditorGuid.HasValue
            ? PropertyEditorValueConvertersResolver.Current.Converters
                .Where(x => x.IsConverterFor(propertyEditorGuid.Value, ContentType.Alias, PropertyTypeAlias))
                .Select(x => new CompatConverter(x))
            : Enumerable.Empty<IPropertyValueConverter>();
    }

Here is a screenshot of the debugger:

And this is where i cannot go any further, because i don't know why IsConverterFor breaks.

I'm using umbraco 7.1.4 and Vorto 1.2 in combination with SEO checker 1.5.2 at the moment.

Steps are:

1. Clean Umb 7.1.4
2. install Vorto 1.2 (via Nuget) or just get the source)
3. Install SEO Checker.
4. Create SEO Checker datatype
5. Create 1 or 2 languages(cultures) in your sites
6. Create Vorto Datatype (textstring for example)
7. Add both datatypes to the same doctype
8. Now on your template (view) try to get the value of the vorto property using @Model.Content.GetVortoValue("Alias") <dont forget the @using Our.Umbraco.Model.Extentsions >
9. Refresh the page and it should break.

We are on a big project at the moment. And i cannot afford to lose one or both of these packages, so i really need your help on this.

Hope to hear from you soon.

Regards, Vishal (Tam Tam)