Forwarding an e-mail causes two copies in sent items?

Question

Hi,

I have a strange issue and I cannot wrap my head around it. When our secretary goes into her Outlook 365, and selects a shared Mailbox, there she forwards the e-mail to someone in the company - the sent items will show two identical e-mails in the shared mailbox. So far I am aware of there isn't a rule on the mailbox or on the server side.
We are using hybrid exchange setup with only one exchange server on-premise and online.
Where can I start to look for the possible cause?

Cheers!

Answer 1

So the only solution which works for us is to remove all the checkmarks from O365 Console -> shared mailboxes:

and do a registry edit i a form of:

HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\Preferences
Note
The x.0 placeholder represents your version of Office (16.0 = Office 2016, 15.0 = Office 2013, 14.0 = Office 2010).

1. On the Edit menu, point to New, and then click DWORD Value.
2. Type DelegateSentItemsStyle, and then press Enter.
3. Right-click DelegateSentItemsStyle, and then click Modify.
4. In the Value data box, type 1, and then click OK.

This only works this way in our case, BECAUSE READ CAREFULLY we DON'T want the following:
when a user sends or forwards an e-mail from a shared mailbox, we don't want this e-mail staying in the private sent items folder of a user, only in sent items of a shared mailbox.

Without his mambo jambo, i think turning on the first checkmark would work normaly for most needs.

Thanks

Answer 2

Hi @Tonito Dux ,
Only one shared mailbox have this issue or or all shared mailbox have?
Is the user and shared mailbox in the on-premises Exchange server or Exchange online?

1.Please try to login to OWA and forward the email, then see if the same issue occurred in OWA. If the issue only occurred in outlook client, please make sure the outlook cilent is the lastest version.
2.Please re-create a new Outlook profile and add the shared mailbox again, then try to forward the email.
3.Create a new shared mailbox and assgin the permission to secretary, try to forward the mail in the new shared mailbox and see if there is the same issue.
4.Please check the message trace in exchange online or message tracking log in on-premises Exchange server to see is there a record of sending two emails.

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Answer 3

Hi LucasLiu,

thank your for replying. The problem actually turned out to be the two check-marks which I put on every shared mailbox in our company:

After I removed the "Copy items sent on behalf this mailbox" check-mark everything was back in order. After sending the e-mail from the shared mailbox's e-mail address it appeared only once.

Cheers

Answer 4

Hi,

I am having this looked by our partner IT company, so far

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\x.0\Outlook\Preferences
   Note
   The x.0 placeholder represents your version of Office (16.0 = Office 2016, 15.0 = Office 2013, 14.0 = Office 2010).
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type DelegateSentItemsStyle, and then press Enter.
5. Right-click DelegateSentItemsStyle, and then click Modify.
6. In the Value data box, type 0, and then click OK.

This worked, but the question is why. Also, in outlook OWA this situation does not happen. I have checked all the rules, read about it on the internet, played with the checkmarks in O354 console but still this looks to me like a bug. I even entered with user credentials on to a test VM just to be sure that her PC did not cause an issue, but on the VM - the same things happened.

Only big change was that we migrated our mailboxes to exchange online.

Cheers