Some of the questions I pose below may not be answerable until (if) you see these symptoms again.<br><br>Did you notice if the "Querying" indicator on the bottom left corner was on continuously, not at all, or turning on and off at interval?<br><br>When you right-clicked on the lower graph, did it have an option to "reset focus to current"?<br><br>If you're using Windows NT/2000, what is the thread count in Ping Plotter when this happens?<br><br>Were there a lot of route changes logged (with a lot of unique hosts)? I've had an instance in the past where a DNS server stopped responding - and locked up all the trace threads waiting for it to respond (this was a local machine problem).<br><br>I've really not heard of this happening in the past - so I can't verify if this is a bug or some other issue. Keep an eye on it and I'd love to get some more information if you see this problem again so it can be corrected.<br><br>Thanks!<br><br>