Duplicate Messages in Outlook Due to Inbox Rules

I've come across the problem of duplicate email messages in Outlook quite often, and it's almost always an Inbox Rule that the user has set (and often forgot about).

With a simple PowerShell one-liner, you can check for such rules and inform the user to disable/delete them, or disable/remove them yourself.

Fire up the EMS (Exchange Management Shell) and run:

Get-InboxRule -Mailbox "user1" |fl

**Note** Change "user1" to the mailbox of the user your checking on.

You'll get an output similar to this:

RunspaceId                        : 53c685d4-326c-4438-b5a0-aa490c4b3762
Description                         : Take the following actions:
                                              redirect the message to 'user1@exchangeitup.com'
                                              and stop processing more rules on this message
Enabled                              : True
Identity                               : Forward Messages to Alias
InError                                : False
Name                                 : [Apply to all messages]
Priority                                : 1
RuleIdentity                        : 5675183204786702859

You can see that the Rule redirects all messages to an alias; which if that alias exists in Exchange will double up messages.

To disable the Rule without intervention from the user, run:

Disable-InboxRule -Identity "Forward Messages to Alias" -Mailbox user1@exchangeitup.com

**Note Change -Identity to the rule name you're disabling and -Mailbox to the user your working with.

It's probably better to disable the rule rather than remove it, but just in case you want to do that, run:

Remove-InboxRule -Mailbox user1@exchangeitup.com -Identity "Forward Messages to Alias"

To remove all Rules from the mailbox, run:

Get-InboxRule -Mailbox "user1@exchangeitup.com " | Remove-InboxRule

That's it; have the user test and verify that there are no more dupe's.