When you delete them from Outlook on the web, they will be deleted from all devices your mailbox syncs with. If you delete the Birthday calendar in Outlook, it will come back within a few seconds, you need to turn it off in Outlook on the web's Calendar Options and choose Turn off the birthday calendar You can delete the Holiday calendar in either Outlook desktop or Outlook on the web. To remove the Holiday calendar, right click on the calendar and choose Delete folder. Search for 'location:country name' if you need to delete Holidays.
The easiest way is to search for 'birthday' or ''s birthday' then Select All and Delete. If you decide to keep the separate birthday calendar, you'll probably want to delete the birthdays from your own calendar.
If you want to remove a birthday from the calendar, you'll need to edit the person's contact. The server created the birthday calendar from your contacts and it is read-only you can turn it off in Outlook on the web's Calendar options but cannot delete individual birthdays from the calendar. A message pops up 'You cannot make changes to content of this read-only folder' I am trying to delete a list of birthdays, but it won't allow me.
