In older versions of Outlook, when you drag a recurring item to a new calendar folder, the recurrence is lost and only the current appointment is moved or copied to the new calendar.
When you use a list view (such as By Category) and drag the recurring appointment to the new calendar folder, the recurrences are preserved.
This behavior changed in Outlook 2010. Now when you can drag recurring appointments to new folders, you are given the option of moving the series or moving just the occurrence. (You can drag to a folder as shown in the screenshots above or to a calendar in side-by-side mode as shown in this screenshot.)
Published October 20, 2010. Last updated on January 9, 2012.