While you can't change Outlook's 18 hour default reminder, you can use VBA to remove the reminder or change it to a different time. While the tweaks here work specifically with reminders on All Day events, this code can be tweaked to do almost anything when a new appointment or event is saved.
Outlook appointments show a drop-down list for Location, populated with the most recently used locations added to appointments. You can clear the entire list but cannot add your own preferred locations, or delete a location from the list.
Question: When I send or receive meeting requests or view other people's calendars, the appointments are off by one hour. This is caused by incorrect time or time zone settings on one of the computers. 1. Verify all computers involved are set to the correct time, time zone and daylight savings time settings in Windows
Microsoft Outlook really seems really bad at handling time zone changes, in part because Outlook uses UTC time for appointments and adjusts the time using the time zone offset configured on the computer. We show you how to avoid problems and introduce workarounds, as well as show you how to update appointments if you move to a new time zone.
The problem: when you have multiple calendars selected in Outlook and close (uncheck) the first calendar, the calendar's name remains in the title bar and taskbar. Any custom views for the original calendar will remain in the Current view picker. This is a known issue. It's not so much a bug but a limitation of
Learn how to change the reminder settings so a reminder is not set on new appointments.