First an apology:I am aware that there are already several other threads on this subject - I apologise for not using one of those but I thought it best to start afresh.A bit of background: We have Exchange 2007 installed on our single domain; single forest. The domain was created from scratch and Exchange 2007 was a clean install. User accounts were re-created and mailboxes transferred from our old domain, with Exchange 2003, using ExMerge. We have a disproportionally high number or shared mailboxes within the organisation. And now the problem:There seems to be an issue with granting the Send-As permission to some shared mailboxes.It was my understanding that in Exchange 2007 granting a user Full Access to a shared mailbox implicitly granted that user the Send-As right. Indeed I have a number of users that are able to successfully Send-As in this manner and the only rights they've been granted is Full Access.That said if I grant Full Access to the shared mailbox to a different user they appear to be able to perform all tasks other than Send-As. To my mind this would indicate that the Full Access permissions have taken affect.Initially granting rights was performed using the command shell, it has been tried through the GUI updates in SP1 and I have tried since using the command shell just in case it was a GUI issue.In a futile attempt I also tried explicitly defining the Send-As right but this had no affect. I've since removed this.How you can help: Have you come across the same problem? Were you able to fix it? Are there any diagnostics I can perform for more information? Are there any event/process traps I might be able to monitor? Give me millions of pounds (or dollars; I'm not fussy!) so I can quit my job and not have to worry about this any more...

Send-As and Full Mailbox Access are different permissions. Full mailbox access does not give the granted account to Send-As the mailbox. how is mail sent, outlook/MAPI or with SMTP

That'll be why it isn't working then! I would have sworn that I'd read that Full Access gave Send-As rights... I feel quite silly now. PS: Email is sent from the Outlook client via MAPI.

Hmm... Just tried adding Send-As rights for a user but it doesn't seem to be working. Would there be some replication delay? Thanks again,

NowI feel like a real idiot! I'd assumed that there was a problem because some were working and others were not. It seems that the users that were working were actually sending 'on behalf of' rather than 'send-as'. I hadn't even questioned my belief in the implicit Send-As granted with Full Access because some accounts 'worked' and they had Full Access but no Send-As.

I ran it to the same issue. This thread helped me to understand what's going on.Hope this helps.