N.B. This page was probably correct correct as of 2011, but is not being updated.

This page provides a little help to anyone who has encountered the "XPath statement produced no nodes to validate" error in ALSB

I got the "XPath statement produced no nodes to validate" error once, when using AquaLogic Service Bus version 2.6.

The exact sentence of the error didn't match any webpages indexed by any of the search engines I tried. So I thought I'd create this webpage.

My understanding is that this error occurs in a "Validate" stage of a message flow, where you have to specify an XPath to select the portion of incoming messages that you wish to validate.

It seems that no additional detail is ever provided. So you just have to work it out yourself. It could be that your namespace is wrong, or your XPath just doesn't work, or the message that was received was wrongly structured.

To help avoid this fairly unhelpful error (and perhaps get a more helpful one instead), it may be best to try to validate at as high a level as possible. (So with as short an XPath statement as possible, not looking very deep inside the messages for the point at which validation should start.)