Outlook 2010 ...messaging interfaces returned unknown error... cannot resolve recipient. When replying

Question

There is a link with someone else who was receiving the same error, but i believe for different reasons.
http://social.technet.microsoft.com/Forums/en-US/outlook/thread/43221dbf-60e1-4afb-8c25-f23f06deed3e
I just performed an upgrade from office 2007 enterprise to office professional plus 2010 today (I am running Windows 7) and I keep getting this error:
Microsoft Outlook
The operation failed.  The messaging interfaces have returned an unknown error. If the problem persists, restart Outlook. Cannot resolve recipient.
P1: 300531
P2: 14.0.4763.1000
P3: 6xk3
P4: 0x80040700
It happens when I reply to an email.  The addresses are in the format which outlook 2003 and 2007 have been using
Webb, Sydney A <[email protected]>
I notice that if I simply type the address:
[email protected]
it will send fine.
I also notice, the format for contacts has changed to Webb, Sydney A ([email protected])
() instead of <>
i assume that is what is causing the issue, but all of my incoming emails are marked with the old style, so when I hit reply I have to retype the addresses every time(even for the same contact on following email replies).  I am sending via POP3(gmail
account in PST is default), but I do have an exchange account configured which I occasionally connect to.
any ideas on how to change the incoming format of messages so the sender's address is in the new format?
I would greatly appreciate any help.
Christopher Webb http://christophermichaelwebb.com

Answer 1

I too updated from 2007 to 2010 and couldn't send group emails.  After reading many of the suggestions here, I discovered a simple solution. I simply clicked on the outlook contact, opened up the file in the address book, and changed the display name.
 I had some addresses that were listed under "display" like this:  John Doe ([email protected]). I changed each of those in the display field to read either John Doe or Doe, John.  I saved the contact and continued.
Note:  I discovered this problem in sending out group emails.  So I opened the groups one by one.  Then I scanned down the list of displayed names, and clicked on any with the combination of name and address to them as an outlook address card.
 In the card, I changed the display name, and then clicked "update" to update the list with the new listing.  Sometimes after updating, the display name had not changed.  Hmmm... I noticed that there were two kinds of card icons to
the far left of the displayed name.  With the lighter-appearing icon, changing did not work.  I had to delete the individual person in the group, and then re-add them by clicking "add member." Now they had disappeared in the listing.  So
I clicked "advanced find."  There I put in their names or a portion of the email address, and found them quickly.  Then I double clicked on the correct listing to add the person back into the group.  
At that point, the icon to the left of the displayed names had changed to a darker icon like the majority of my members, and clicking on the name to open the file worked, as did changing the display name.  Then when I clicked "update", I had
the correct display name.  The changes stuck.  I think perhaps the lighter-appearing icon were adds to the group that I had not added to my outlook address book, but only to the group email.  It was so long ago that I added these members originally
that I have no idea any more. 
So now we know two things:  Display the name only, or display the email address only.  Both work.  Just don't display the combination with parentheses.  I wondered if perhaps the Outlook 2010 couldn't find that kind of listing referenced
in the outlook address book, and that's what is causing this hangup?
I hope this helps someone save a lot of time and irritation.  It was a fairly easy fix.