Graph disapears

This may be a setting proble but I can’t figure it out. The graphing has been fine for days then when I swiched the computer on this morning the graph was blank and has been steadily building up OK during the day. Do I have a setting on the Vantage pro or WD wrong?

it will be the change in month
if you had the pc/program running duiring the month change over time it would have been OK (like it was for me)

Thanks for that. It seems a weakness that all graphing data is lost when the month changes. I had thought that the data was stored securely in the Vantage and then downloaded when the programs is started. This might happen for all sorts of reasons not least when power cuts occur. Likewise not everybody can run their machines 24 hour per day. Thanks anyway.

no, its not lost if the program was running at the time, like it was for me
no loss here