With version 2.20 the default file extension for the PingPlot files was changed from PPS to PP2.<br><br>The "Save Sample Set" dialog still defaults to displaying the PPS files meannig it does not show samples saved with version 2.20. It should default to displaying both *.pps and *.pp2 files.<br><br>The "Load Sample Set" dialog now uses displays and uses PP2 though it too should display the both PPS and PP2 files and just save them as PP2.<br><br>Marc<br><br><br>