OK - Answer.

Create an XML Schema Collection using:

CREATE XML SCHEMA COLLECTION dbo.MyXMLSchema

AS

N'<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema">

<xs:element name="rows">

<xs:complexType>

...

Eirikur, thanks for the suggestion on the ( OPTIMIZE FOR ( @xmlstring = NULL ) ) .

While it didn't solve the problem, it led me to a post with...

Thanks for the reply. Unfortunately, the OPTION ( OPTIMIZE FOR ( @xmlstring= NULL ) ) didn't help.

We're on SQL 2008 R2 SP2.

Bob