In The Events Calendar the ability to add an event to your calendar via an iCalendar file is now in the core plugin. This used to be a feature only in the Events Calendar PRO plugin.
Out of the box this works great for either Google Calendar or Apple’s Calendar. However, in Outlook, adding the event would create a whole new calendar instead of adding the event to the user’s default calendar. It seems that the issue is simply the addition of the X-WR-CALNAME header in the generated iCalendar file. This header is valid according to iCalendar.
Unfortunately Outlook doesn’t seem to like this and its inclusion causes the creation of an entirely new calendar and not just a new calendar event. The solution is to remove this line. When this is done an event will be added to the default Outlook calendar.
A while ago I wrote a quick function to remove this line. This solution was made much simpler by Modern Tribe’s inclusion of a nice filter hook. Lately I’ve found more people having this issue and having difficulty implementing the fix. In order to simplify the solution I’ve converted the solution to a plugin.
So go grab The Events Calendar Outlook Import Fix plugin from the WP.org repo. All you have to do is install and activate. Please bear in mind, when this plugin is active users of other calendaring apps may have problems. This is a solution for sites whose users only use Outlook.