Well this is the problem! I had expected that WD would read the data from the logger and thensave it somewhere. What puzzles me is does the logger get completly cleared when full or does the earliest record get dropped each time a new one is generated? If the logger is cleared why does WD never pick up the cumulatives from the logger after all the data has been lost? It seems to me that there must be some simple logic error somewhere but it is puzzling that it does not affect everyone.