Most manual merge methods won’t deal with duplicates, but some tools can help.
Softaken Merge vCard Pro is a solid option because it not only
combine vCard Contacts but also ensures your contact list remains clean and well-structured. While it doesn’t automatically delete duplicates, the preview step helps you identify and exclude them before merging. Another approach is to merge with Softaken, then run the result through a contact cleanup tool. The key benefit is that it preserves every detail and merges contacts from different sources — Outlook, iCloud, Android, etc. — into one properly formatted file.