A few days ago I experienced an interesting issue when using the Calendar E-Mail Extension with content approval enabled.
This is what happened:
When I then logged in as another user (without manage lists and approval permissions), the deleted occurrence is still visible and if I clicked on it, I received the error “Item does not exist. It may have been deleted by another user.”
So let me explain what happens if a single occurrence of a repeating event is deleted or changed.
If an instance of a recurring event is changed or deleted, SharePoint adds a new event to the list with a different event type.
There are 4 types of events:
So for example, if I delete a single occurrence, a new item with Event Type 3 will be created.
So the problem now is that if content approval is enabled on the calendar, this newly created item is pending. If a user without manage lists or approval rights opens such an occurrence, it displays the “item does not exist” message.
If it’s a recurrence exception, the user who made the changes can at least access the exception and approve it manually, but if it’s a deleted instance it’s not easy to access the item, especially in the calendar view.
A deleted instance is only visible in the “All events” view and can be identified by the title “Deleted: [Title]”.
One possible workaround would be to approve newly created items automatically with a simple SharePoint Designer Workflow if the EventType is 3 or 4. Make sure the workflow is configured to start automatically when an item is created.