When the OWL + USB monitor is connected to the PC the background service will start to download the data from it into the database file.
This can take a short while to start, as the monitor will wait for the next new data to be received before commencing the upload. For a full 30 days of information you can also expect something around 5Mb of data to be uploaded, this can take up to 5 minutes depending on activity levels.
When The OWL +USB Software is started it will attempt to make graphs from the data in the data base. If the upload is incomplete then the graphs will be similarly incomplete.
Please wait a few more minutes, then Close the graph using the graph window X button.
Initiate new graphs using the new Chart button top right of the software.
If the data upload is complete then the graphs will be completed.
Two other issues have in the past resulted in data loss.
The first was associated with older drivers for the software, which have been replaced, please ensure your software version is fe-02-00-11 at a minimum.
If the OWL monitor loses pairing with its transmitter, then there will obviously be lost data during that down time. This data will be unrecoverable.