If you want to set outlook to follow the ISO week you need to make the following changes:
Outlook 2007 and previous
Tools-> Options…-> button Calendar Options…
File-> section Options-> section Calendar
Set the following Options:
First day of week: Monday
First week of year: First 4-day week
You may find this code block handy:
/// Gets the mail item selected in the explorer view if one is selected or instance if that is the view active.
/// The instance containing the event data.
/// A Outlook.MailItem for the mail being viewed.
private Outlook.MailItem GetMailItem(RibbonControlEventArgs e)
// Check to see if a item is select in explorer or we are in inspector.
if (e.Control.Context is Outlook.Inspector)
Outlook.Inspector inspector = (Outlook.Inspector)e.Control.Context;
if (inspector.CurrentItem is Outlook.MailItem)
return inspector.CurrentItem as Outlook.MailItem;
if (e.Control.Context is Outlook.Explorer)
Outlook.Explorer explorer = (Outlook.Explorer)e.Control.Context;
Outlook.Selection selectedItems = explorer.Selection;
if (selectedItems.Count != 1)
if (selectedItems is Outlook.MailItem)
return selectedItems as Outlook.MailItem;