The Calendar app in iOS 9 comes with two new tricks; it can tap into your Mail app and show you which events you’re supposed to be attending on the Calendar itself. It can also get a traffic report and let you know when to set out for an event so that you get there on time. That said, if you aren’t too excited about the changes you might be searching for an off button to these Mail app events. The Calendar app will automatically show these events if you’ve added an email account to the Mail app. If you find it annoying or unhelpful, there’s a pretty simple way to turn it Off.
Open the Calendar app and tap on ‘Calendars’ at the bottom of the screen. Here you can manage which calendars appear on the app. Events from the calendar you choose to enable here will appear in the app. As of iOS 9 you will notice a new calendar that’s enabled by default called the ‘Events found in Mail’ calendar. Disable it here and you will no longer see events from the Mail app appear in the Calendar app. This is of course a soft and reversible way to turn the events off.
If you want something a little more permanent, go to Settings>Mail, Contacts, Calendars and at the very bottom of the Calendar app’s settings, turn off the Events found in Mail option. The warning label under this particular setting duly warns you that any unconfirmed events will be deleted with no way of getting them back. It will also prevent the Calendar app from fetching any new events from the Mail app.