We allow users who don't have an internal Exchange mailbox to specify an external E-mail address to use which appears in the GAL. Some of these users specify the same generic (eg ABCconsulting@gmail.com) address so there are dups in the GAL. When someone sends one of them a message by using the GAL, the following NDR comes back .. "A configuration error in the recipient's e-mail system prevented delivery of this message. Two recipients are configured with the same e-mail address. Contact your administrator." If the internal Exchange user just enters the external email address as text the message goes through fine. Is there any way to make this work if the address is external? We're on Exchange 2007.

Two recipient objects are not allowed to have the same e-mail address. The tool you used to create this situation should have made a best effort to prevent you from doing this, but apparently you have slipped through the safety net. The only answer I have for you is to choose one of the recipient objects you want to keep and delete the other one that has the same e-mail address.

Hi,This is by design. Exchange does not allow this behaviour to be generated. Please remove the duplicate email address based on Ed suggestions.ThanksAllen

Does anyone have a suggestion or a workaround aside from removing the duplicate email addresses? External users who appear in the GAL provide their own email address, which is often shared by several employees. I don't understand why Exchange would care about email dups for non-Exchange mailbox users.

I am working on a script that will mail enable some users in my domain with external addresses. I need to programatically detect when a specified recipient address has already be used to avoid the "Two recipients are configured with the same e-mail address" issue. Do you know how to check if the specified address has already been used form Perl, VB or any other manner? Your help would be appreciated.