For better control, you can sort your inbox to identify and delete duplicates manually. How To Remove Duplicate Emails In Microsoft Outlook
Before running this, export your contacts as a backup (File > Open & Export > Import/Export > Export to a file > CSV). This way, you can restore them if something goes wrong. remove duplicate outlook
Navigate to the Home tab and locate the Clean Up button in the Delete group. Options: For better control, you can sort your inbox
Deletes duplicate messages within the selected folder. For better control