The wrong name appears attached to my email. It is not on my vCard - I have checked. I have deleted the card of the person who's name is used. I have checked "Previous recipients" and he does not appear at all. Somehow, somewhere at some level, Mail thinks my email address is titled with his name.
I think I found the problem -- I've seen this problem happen across 3 different macs in my extended family. Today, in utter frustration, I started searching for a solution...
Previous Recipient list was not the problem. It was Contacts.
Do a Spotlight search on your email address (the actually address) and see if you have extra contacts show up with that same email address. In my case, I did. Somehow Contacts was making all sorts of weird connections.
For instance, in my address book, "Prescott Police" had 7 (!) completely unrelated (and often obscure/hardly used) email addresses associated with it.
I edited the contact and deleted the extra email addresses associated with it.
I then stopped and restarted Mail, and the email address in question showed up with the correct name.
I have no idea how Contacts ended up making such strange associations, but so far I've been able to "fix" 2 errant names that I came across in the past 30 minutes.
I'm still on 10.10.5 (I never upgrade OS in the midst of a major project), and my mail services (IMAP) include Pair, iCloud, Gmail, and icdSoft.
Mail > Preferences then click on the account in question on the left.
The "Full Name" field is likely what you are talking about. Verify that it is correct.
If it is not in
Right-click on the email address, click Add to Contacts (and add it as a new one), then highlight both the old and new name and right-click to Merge the two files. Edit from this point.
I have had the same reported problem but with Outlook for Mac (version 16.23).
My name was stated correctly everywhere (account settings on the web and in Outlook), but when people replied to my message an awkward name was shown.
I finally found that I added my email address with that awkward name as a contact of another mailbox configured in Outlook. I have now deleted the contact from that Mailbox and waiting to test if the problem is solved as expected.
That's really weird!
I would like to echo the advice given to 1) check the name on the Mail account and 2) check any/all names associated with the e-mail in Contacts and make sure the e-mail is not associated with an incorrect name/contact card. Restarting Mail is necessary to synchronize things once the changes/updates are made. I was having this problem also and taking these steps fixed it.