It seems that in JBM 1.3.0.GA on AS 4.2.0.GA the processing of TopicSession.DUPS_OK_ACKNOWLEDGE for topics is broken. It used to work in previous versions up to JBM 1.2.0.sp1 on AS 4.0.5.GA. The first indication of the problem is that in listMessageCountersAsHTML() of the ServerPeer MBean the Depth counter of the topic will always grow, although the messages are delivered to the subscriber. When trying to close the consumer, the following exceptions are thrown and the subscription is leaked: java.lang.IllegalStateException: Cannot remove references while deliveries are in progress, there are 147 javax.jms.IllegalStateException: Cannot find binding for topic sub with queue name: a5g2ys-jbgoe3-f2yes1cr-1-f2yew8i8-q A workaround is to use AUTO_ACKNOWLEDGE. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4054656#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...