SQL Server does not handle comparison of NText, Text, Xml, or Image data types.

When adding XML to an XML field in SQL server via Linq to SQL it all works fine, however when you try and update this XML field, you get this error;

SQL Server does not handle comparison of NText, Text, Xml, or Image data types.

Fix to my solution was to edit the dbml and set the updatecheck to false

<column canbenull="true" dbtype="Xml" name="OrderXML" type="System.Xml.Linq.XElement" updatecheck="Never"></column>


Works like a dream now.