I recently took over managing a single SBS 2008 environment with Exchange 2007. I've updated it to the latest SP3 two weeks ago. This problem was occuring before applying the service pack. What happens is a USERA creates an appointment and invites people in in the outside world to this appointment. When people inside the network or outside accept the appointment, USERA gets the acceptance email and everything is fine. For everyone who accepts the email, they get a bounce back saying a USERB doesn't exist. USERB was never invited to the meeting and doesn't even exist in the active directory. My guess is USERB did at one time exist and have a working email account. I've checked several areas looking for maybe a forwarding entry or something cluing in on where this entry might be. I used adsiedit to search for USERB and I haven't found anything. Here is the content of the bounce message Your message did not reach some or all of the intended recipients. Subject: Accepted: Test Invite Sent: 12/29/2010 10:46 AM The following recipient(s) cannot be reached: USERB on 12/29/2010 10:46 AM The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address. <domain.local #5.1.1 smtp;550 5.1.1 RESOLVER.ADR.ExRecipNotFound; not found> Any ideas on where I should look or what I should try?

Check UserA's delegates. http://support.microsoft.com/kb/312433 The article refers to Mdbvu32.exe. You should now use mfcmapi http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/743b0de8-3e23-438d-b990-dc9c315f96a8/

Thanks for this - I was able to use the second links SECOND utility to delete the entry detailed in the steps.