I have a server running Windows Server 2008 R2 with Exchange 2010 on a recently upgraded forest of 2008 R2. (It was a hybrid for a long time before that).
The Way It Was: We had email being forwarded from a local mailbox to an offsite email account (on another organizations exchange server) . The box to have it sent to both the forwarded and local mailbox was checked.
What I did: Under the mailflow settings tab, under delivery options: I unchecked the "Forward to" mailbox.
What Happened: All email was no longer being delivered to either the local or the forwarded mailbox.
Troubleshooting: We determined that when we were forwarding email with messages going to both local and forwarded address, everything worked. When we removed it, no one received email.
I went into the attributes and found that the msExchGenericForwardingAddress had the forwarded email address. I unchecked the email forwarding box,. Removed this email address and email worked for the local mailbox as per normal.
The Problem: Where did the email go? I checked the outbound spamfilter and during the time in which forwarding email was unchecked it did not go into the local mailbox, but neither was it forwarded. I checked the transport rules and it seems to be forwarding correctly, but the email does not reach spamfilter (postini).
Other: Journaling is not active, neither is the email able to be restored from deleted items (as it never reached the mailbox in the first place), so retention policies are pointless.
I am looking to find / restore the emails lost for about 4 hours this morning.
Thank you all!