On 28 Feb 2011, at 10:25, Kino wrote:

> On 2011-02-28 [+0900 JST], at 6:44 PM, Doug Browne wrote:
> 
>> I have used Mail for years, adding, removing and editing address without any problems. Suddenly one address refuses to be changed! No matter what I do, the original version always comes back. The new version is, of course, in the Address Book. 
> 
> I'm not very sure but...
> 
> 1. Quit Mail if it is running;
> 
> 2. Trash '/Users/you/Library/Application Support/AddressBook/MailRecents-v4.abcdmr'.
> 
> If this works, Mail stops suggesting past mail addresses not in Address Book.
> 
> 
> Kino

I don't want to do this because I have dozens of address in Mail that are not in my Address Book and I do not want to lose them.

Hamid, success! Your suggestion to click on the down arrowhead at the end of the unwanted address then apply 'Remove from Previous recipients' did not work on the first attempt. But after restarting the Mac your suggestion has done the job. No crashing either. Thank you everybody for your suggestions.

Doug