So someone has been messing with out GAL and a few users are this error:
Delivery has failed to these recipients or distribution lists:
There is a problem with the recipient’s e-mail system. More than one user has this e-mail address. The recipient’s system administrator will have to fix this. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator and then try resending the message after the problem has been resolved.
#550 5.1.4 RESOLVER.ADR.Ambiguous; ambiguous address ##
Clever Trevor came up with this really cool way to find the duplicate users. Open up AD Users and Computers. Up by your domain name, right click and select find. In the Find dialog, click on the Find drop down and select Custom Search and click on Advanced
This will search for the specified email address on all object types:
You can always change the object category (to users, publicfolders, etc) if you want to narrow down/speed up the search.
How cool is that! Thanks Trevor