Catalog Ex****t XML File has trailing rubbish

When I ex****t a catalog using the Catalog Administration tool I am getting 
rubbish past the ending XML tag.  Here is a snippet.

(trimmed the beginning of the file)
      <Description Value="Warm Water Tanks" language="en-US" />
    </Category>
  </Catalog>
</MSCommerceCatalogCollection2>der" language="da-DK" />
      <Description Value="Warm Water Tanks" language="en-US" />
    </Category>
  </Catalog>
</MSCommerceCatalogCollection2>"??" language="ja-JP" />
    </Property>
    <Property name="OnHandQuantity" dataType="real" BuiltIn="1" 
id="CatalogProperty64">
      <DisplayName Value="Onhand Quantity" />
      <DisplayName Value="Bestandsmenge" language="de-DE" />
      <DisplayName Value="Onhand Quantity" language="en-US" />
      <DisplayName Value="Quantité en stock" language="fr-FR" />
      <DisplayName Value="????" language="ja-JP" />
    </Property>
(trimmed to the end of the file)

So far I am getting around the problem by manually editting the ex****t
file. 
 It will happen fairly consistently but not for every catalog every time.