If keeping up with Outlook's idiosyncrasies doesn't drive you batty, you haven't opened appointment forms using every method available and ticked the All Day Event box off and on to check the reminder settings.

The problem? Opening an appointment by double clicking on the monthly calendar or using click & type creates a new appointment with the reminder turned off. Using the New Appointment command to open an appointment then toggling All Day Event on and off results in 15 minute reminders or 0.5 days reminders.

A lot of users live in the Monthly calendar view. They double click on a date to open a new appointment form, untick All Day Event and create an appointment. While it may not be the most efficient method, it works and a lot of people do it.

Double-click on a date in the month view in older versions of Outlook, and the appointment form opens with an 18 hour reminder. Unticking All Day Event changes the reminder from 18 hours to your default reminder for timed events, then back to 18 hours when you tick All Day Event again. However... this does not work as expected in Outlook 2013. When you open a new appointment form by double clicking on a date in the calendar, the reminder is not set by default for All Day Events. Unticking All Day Event converts the event to an appointment but it does not set a reminder for timed events using this method.

Right click on the monthly calendar and choose New All Day Event (or use New Items > All Day Event), and the reminder is 18 hours. Untick all day event and the reminder is your default for timed events. Tick it again and the reminder is 0.5 days (12 hours). Twelve hours is the new default reminder for all day events, but dang, changing it to 12 hours everywhere would have been nice.

Using the "click & type" feature in Outlook 2010's monthly view sets a reminder on All Day Events. Using click & type in Outlook 2013's monthly view does not set a reminder. (Click & Type is the feature where you can type in on a date or time period to create a quick appointment without opening an appointment form.)

Use a macro to set a reminder

You can use this macro to set the reminder. This will cause the All Day Event to use an 18 hour reminder. Unticking All Day Event will keep the default reminder but clicking in All Day Event again will change it to the new all day default of 12 hours.

This macro works on "click & type" as well as double-clicking on a date or using the New button or keyboard shortcut.

To use:

1. Set macro security to low in File, Options, Trust Center, Macro Security. You can sign the macro using selfcert after you test the macro.
2. Open the VBA Editor using Alt+F11.
3. Expand Project1 and double click on ThisOutlookSession.
4. Copy the code below and paste it in to ThisOutlookSession.
5. Click in the Application_Startup macro and click the Run button or press F8 to test it without restarting Outlook.

See How to use Outlook's VBA Editor for screenshots and more information.

Test it by double clicking on a date in month view. This also set the reminder for appointments created using click & type.

Private WithEvents m_Inspectors As Outlook.Inspectors
Private WithEvents m_Inspector As Outlook.Inspector

Private Sub Application_Startup()
  Set m_Inspectors = Application.Inspectors
End Sub

Private Sub m_Inspectors_NewInspector(ByVal Inspector As Outlook.Inspector)
  Set m_Inspector = Inspector
End Sub
 
Private Sub m_Inspector_Activate()
 If TypeName(m_Inspector.CurrentItem) <> "AppointmentItem" Then
  Exit Sub
 End If
If m_Inspector.CurrentItem.AllDayEvent Then
    m_Inspector.CurrentItem.ReminderSet = True
End If
  Set m_Inspector = Nothing
End Sub