We have a few Users that run Outlook on 2 PCs and A Mac.   Often there are 2-3 copies of the same SPAM/Junk mail in the Junk mail folder.   We have found that this happens when we have the Outlook Application running on one or more Computers.

Ironically enough it really only seems to happen to actual SPAM, not the legitimate messages that end up in the Junk mail folder.

Is there a way to prevent this Duplication?

Running Outlook 2010 (PC), 2013(PC) and 2015(Mac)

!

Hi,

Please check if your junk e-mail protection level has been set to Safe Lists Only, I've seen some similar issues when the configuration is done like this.

Please refer to this thread below, I think Alan.Gim's reply has explained the thing pretty clearly:

https://social.technet.microsoft.com/Forums/exchange/en-US/c03e9c15-92ff-4c81-a97a-b2686d566308/duplicate-emails-appears-in-junk-folder-when-accessing-common-mailbox-from-multiple-workstations-in?forum=exchangesvrclientslegacy

So if you haven't, please install the Anti-Spam feature on the hub server, and then see if the issue still appears

Enable Anti-Spam Functionality on a Hub Transport Server

Melon Chen

Forum Support