To do so please go to the Tools > Charts and type 9999999999999 into Max bars in chart and into Max bars in history. Then open a M1 chart on the pair you wish to back test.
After that click File > Open Data Folder > History > Midas FX-Live and then close the Midas terminal, delete the chart files in this folder.
And by doing so you will download all available history on our server. Any history not shown here is no longer stored on the server. You will download everything available. We do not store for long periods of time to keep the servers working efficiently.