We have migrated from Exchange 2003 to Exchange 2007. When a user sends a message as a shared mailbox, the FROM field contains "<username> on behalf of <mailbox>" instead of just "<mailbox>." How do I get rid of "on behalf of"?

you must grant "Send As" permissions rather than "Send on behalf of" permissions.

Even if you have full rights to the user ID, you cannot send on behalf of the user. You must also grant Send on Behalf rights in EMC to send an e-mail withthe shared mailbox as From. I gave myself full rights in ADUC, and FullAccess and SendAs in EMS, and Send on Behalf in EMC and I still get "Frank Wayne on behalf of <shared-mailbox>" on my message.

Look at the user account you want the Send As permissions to in Active Directory Users and Computers. View the Security property page and give yourself "Send As" there. I think this will take care of you.

I tried that and it didn't seem to work at first, but now it works fine. It was driving me crazy (and my users) but now it seems to be fixed. Thank you for the advice.

Hi Frank, I am having the same problem, I have "Send As" assigned also "Delegate" access but removed the "Send on behalf" permission and I get permission issue, but when I assign the "Send on Behalf" permission, it works, except the from field has "On Behalf Of". How long did it take to work without "Send on Behalf" permission assigned? Thanks.

As far as I can tell, youshould notremove the "Send on Behalf of" permission in the EMC. The user must be in that list as well as have Send As permission in AD. I also grant SendAs permission using Add-MailboxPermission in the EMS, which seems to be different from either of the other permissions. After I assign all the rights, mail goes out correctly within 24 hours.