Pete, here is some additional data.<br><br>I deleted the log file and resumed my plot. On the first failed ping PP went CPU bound and created a 2.1 megabyte log file that started out with "Trace Session Started at: 8/18/2000 9:07:22 PM" and showed all of the pings that were over 1000ms.<br><br>I exited PP (saying No to the save-data prompt) and started a new copy of PP with the old PP2 file. This time the log file grew from 2.1 to 4.2 megabytes It looks like you must have a pointer to the last data element you have logged. When you want to add a new item to the log file you start at the last logged element and work you way out from there. When loading a PP2 file you end up resetting the pointer back to the beginning of the plot data meaning the next time something gets logged you end up dumping the entire plot history which accounts for the CPU bound condition I saw.<br><br>related suggestion / feature request. When a plot is stopped and resumed you should fire an alert. If any of the alert monitors have logging enabled the code should append a line to the log that the plot was stopped or resumed.<br><br><br><br>