How do I delete all but one (no duplicate contacts) in macOS 10.13 / iTunes 12.7.0.166

Hi,

I'm not sure I understand your question but it sounds like you wish to have only a single contact left in your address book.  e.g. imagine you have 10,000 contacts, it sounds like you are asking how to get rid of 9,999 contacts.  If so, read on:

Assuming that the duplicate is actually there, i.e. not "found in Mail" or other category, then the process is simple:

1)  Open "Address Book", the actual app for holding contacts.
2)  Click in the contacts pane and then choose "Select All" from the Edit menu.
3)  Command-Click on the one you wish to keep.
4)  From the Edit menu, select "Delete Cards"

That should do it.

If you are seeking a solution to another problem, could I ask you to rephrase your question and perhaps give an example to better illustrate the problem?

Sorry, I did not phrase question correctly.

What I want to do is eliminate duplicate contact entries in macOS High Sierra.

For example, there are 12 duplicate entries (records) for 'Ann Staver' in macOS High Sierra Contacts, whereas there is only one entry for  'Ann Staver' in my iCloud Contacts account.

I want to delete all but one of the entries for  'Ann Staver' in macOS High Sierra.

The same process should be used to eliminate duplicate contract entries in the remaining Contacts records. So, I will end up with same name records, but only one copy of each.

Helps much, but still some manual search/delete - Thanks