The first day of the week, as shown in pop-up calendars used to select transaction dates, due dates, and so forth, can be chosen to match the usual practice at your location or your personal preference.
Click on the Preferences tab at the top of the Manager window, then the day of the week currently in use under the
First Day of Week heading:
Select the desired day from the menu:
Click Update to save the change. Pop-up calendars will now display in the new format: