Duplicate emails in User and Shared mailbox

Question

In Exchange Online, can mail flow rules be created to delete duplicate msgs when
the same email is sent to both the Primary and Shared Mailbox(for which
primary is included)? I do not want the same email in both mailboxes.

Example:
I have emails where a message To: Primary and CC: Shared maibox for
Office365, where I am also a member of the Shared mailbox. I do not
want duplicate emails to be delivered to both Primary and Shared.

Answer 1

Hi @Ken Takayanagi ,

Viewing the rules, I came up with this rule.

Great to know that you've already thought of a solution and really appreciate it for your sharing!

By the way, since the Microsoft Q&A community has a policy that "The question author cannot accept their own answer. They can only accept answers by others.". and according to the scenario introduced here: Answering your own questions on Microsoft Q&A, I would make a brief summary of this thread:

[Duplicate emails in User and Shared mailbox]

Issue Symptom:
I have emails where a message To: Primary and CC: Shared maibox for
Office365, where I am also a member of the Shared mailbox. I do not
want duplicate emails to be delivered to both Primary and Shared.

Solution:
Apply this rule after the message arrives
where my name is in the To or Cc box
and with X-Original-To: "groupemail" in the message header
move it to the "duplicate" folder (can also delete it)
Aside: "Cleanup Folder" also does delete the duplicate, however, it doesnt do it in real-time.

You could click the "Accept Answer" button for this summary to close this thread, and this can make it easier for other community member's to see the useful information when reading this thread. Thanks!

Answer 2

The issue isnt where to place the captured msg. The issue was how is the duplicate msg. I noticed with group emails that get forwarded the header shows:
X-Original-To: "groupemail"
Delivered-To: "user email"

Viewing the rules, I came up with this rule.

Apply this rule after the message arrives
where my name is in the To or Cc box
and with X-Original-To: "groupemail" in the message header
move it to the "duplicate" folder (can also delete it)

Aside: "Cleanup Folder" also does delete the duplicate, however, it doesnt do it in real-time.

Answer 3

Hi @Ken Takayanagi ,
I would suggest you could create a rule in outlook to move the emails with addressed the shared mailbox to the deleted items.
You could refer to the following steps to create the rule:
1.Click the “create rules” in the Home tab

2.Click the button of “Advanced Options”

3.Select the option of ” send to people or public group” and then choose the shared mailbox address, click the Next.

4.Select the option of ” move it to specified folder” or Select the option of ” delete it” , click the Next.

5.click the Next in the page of select exceptions.

6.Specify a name for this rule and click Finish.

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