When you import items into Microsoft Outlook and you add the contact as aduplicate, or if duplicate detection is turned off, there is not an option to remove duplicate items after you import. This article explains one method to delete duplicate items after you complete the import process.
How to Delete Duplicate Items
Use the following steps to duplicate items:
On the View menu, point to Current View, and then click to change the folder view to a table type view. For example, use the following view and field combinations:
Right-click a column heading, and then click Field Chooser.
From the list at the top of the Field Chooser, click to select the All <item name> fields.
Drag the Modified field to the table heading.
Verify that the duplicate items have a unique date from the original set of items. If it is unique, click the Modified heading so that the items are sorted by this field.
Click the first item in the set that you want to delete, scroll to the last item in the set that you want to delete, and then click the last item while you hold down the SHIFT key.
Press DELETE to permanently delete all selected items.
For additional information about circumstances that cause duplicate detection to be turned off, click the article number below to view the article in the Microsoft Knowledge Base:
220837 OL2000: How to Turn Off Detection of Duplicate Contacts