You need to have the switch on under control panel, data logger setup
and then when wd starts up, the irox history window should show
but for first time use, WD does not know where in the memory to find the latest data (from 0 to 3140 (and the amount of memory depends on the firmware version)
so try manualy setting the history number (and you can get it to jump forward) until history data starts to show up
(then once wd finds the needed history data (note you can force set the time to get the data from in the data logger setup before restarting), then the next time wd starts it will know where to look