Calendar Items Disappear/Reappear on iOS Devices


If calendar items keep disappearing and reappearing on an iOS device, this could be due to large attachments in calendar entries.  Check the mailbox for any calendar invites with large attachments.  If the attachment is needed, download it from OWA or Outlook and then delete the request or at least the attachment.


If attachment size does not appear to be the issue, it could be caused by corrupt item(s) in Exchange calendar.  Perform the following:


  • Export calendar from Outlook.
  • Delete all events (so there are no events on the exchange server).
  • Double check that no stray events remain on the server.
  • Open calendar on iOS device so it looks to the server.  (All events should now be purged)
  • Now import backup/exported calendar into Outlook.
  • Make sure all events now appear on the server again.
  • In calendar settings, turn Exchange off then on again.
  • Finally open calendar to fetch Exchange events (this will take a while as it's starting afresh).