On Monday Microsoft Product Support Services confirmed to us that the issue mentioned in our previous blog entry is indeed an error that was introduced in the “February Cumulative Update (CU) / Service Pack 2″. The problem has been identified and is now being worked on but at the time of this writing there is no solution yet. We will update this blog accordingly as new information becomes available.

The symptoms of the issue are:

• When sending a new message on behalf of a shared mailbox account where you have full “Send as” privileges (as opposed to “Send on behalf” or “Delegate” rights), the message stored in the Sent Items folder will appear as if sent with “Send on behalf” rights, i.e. the sender will appear as “User on behalf of Account” rather than just “Account”.
• When replying to a message in a shared mailbox, after the message has been sent, Outlook completely resets the sender information to the current user so that messages stored in the Sent Items folder no longer contain any information about the sender that appeared at the recipient, i.e. the sender will be shown only as “User” rather than “Account”.

Note again that this only affects the local copies of your sent messages. The recipients of your messages will always see the intended sender.

Note that this issue is independent of Lucatec^® Mask and can unfortunately also not be fixed or worked around in an acceptable way from within the addin. This will have to be resolved by the Office team themselves.