Viewing events in delegated Calendars when using iCal with CalDAV

When iCal is connected to Kerio MailServer via CalDAVCalendaring extension to WebDAV that enables you to synchronize calendars. protocol, users can manage shared access to their Calendars through the iCal delegation feature.

In specific situations, after selecting the delegated Calendar of another user, you may not see any of the shared events. This can happen through a variety of known circumstances, specifically when Calendar data has been imported from other Calendaring systems, or there has been some type of corruption to the file system (e.g. restored from a broken RAID).

Kerio MailServer 6.7.2 significantly reduces the possibility of this circumstance by incorporating sanity checks on synchronized Calendar data, and stripping invalid data. If you are experiencing this issue, make sure to update to the current version of Kerio MailServer.

It is important to note that the upgrade will not correct any existing Calendar events that have already been synchronized to Kerio MailServer. It is therefore necessary to manually identify and delete these events, which are causing a break in the synchronization.

The following steps describe the process of using webmail to move all events from the affected Calendar to a temporary Calendar, then moving back only the properly formatted events.

  1. Log in to the webmail account of the user who owns the affected Calendar. If their Calendar folder contains many items, it is recommended to set the number of displayed messages (located in Settings > General) to 200.
  2. Right click Inbox and create a new sub-folder calendar_temp and assign it as a Calendar type folder.
  3. Right click Calendar folder and choose Move or copy all.
  4. Select the new calendar_temp folder as the destination and choose Move. This will move everything to the new calendar, including events with invalid data.
  5. Now select the calendar_temp folder and enable the list view from the menu at the top of the calendar window.
  6. Select the first event, then hold the Shift key and select the bottom event. This should select all events in the window.
  7. Drag these items into the original Calendar folder. Repeat this process until all calendar items have been manually moved back into the original Calendar folder.
  8. Make sure to include recurring events as well, as the list view of recurring events is selected as a separate menu item.
  9. At this point you may delete the calendar_temp folder.


Although you won't see any information remaining inside the calendar_temp folder, it might actually contains the improperly formatted events. The action of Move or copy all transfers all of the data, including the broken events, while the action of manually selecting the visible events and moving them back preserves only the properly formatted events.