Any calendar that you have created can be deleted except the primary Outlook calendar which is used for meeting requests that you send and accept. Additional calendars that you open, such as shared, team, or SharePoint calendars can be removed so that they are not listed in the Navigation Pane or appear in the Calendar view.
What do you want to do?
Delete a calendar
In Calendar, under My Calendars, right-click the name of the calendar that you want to delete.
Note: You cannot delete the primary Outlook calendar that appears when you first use Outlook.
Click Delete Calendar.
To confirm the deletion, click Yes.
Delete all items from the primary calendar
Although you can’t delete the primary Outlook calendar, you can delete all the items on that calendar.
Warning: The following steps will delete all items in your calendar, including holidays that are automatically added to the calendar. You can replace default Outlook holidays that are deleted during these steps, but all other calendar items will be permanently deleted.
In the Navigation Pane, under My Calendars, click Calendar.
On the View tab, in the Current View group, click Change View, and then click List.
Click in the item list, and then press CTRL+A.
All items in the list should now be selected.
Remove shared, team, group and SharePoint calendars
When you open these calendars in Outlook, they are added to the Navigation Pane in the Calendar view. This enables you to quickly view the calendar at a later time with only one click.
To remove shared, team, group, and SharePoint calendars, do the following:
Right-click the name, and then click Delete Group or Delete Calendar.
The calendar is removed from the Navigation Pane and no longer appears in the calendar view. The calendar itself is not deleted as you were only viewing a copy of the information.