Environment is Exchange 2010 SP2 & Outlook 2010 SP1.
When a user tries to open a recurring appointment on a shared calendar by selecting "Open this occurrence" they receive an error that says, "Cannot open this item".
If the user selects "Open the series" the appointment opens just fine.
The permissions on the calendar are Default: Author. If I change the permission to Default: Editor they do not get the error but I do not what them to have editor permissions.
I found a KB article about a similar issue but it was for Outlook 2007.