Outlook has (in the POP3 account properties) the option 'leave messages on server'. This makes sure that polled messages remain on the server, for example to allow you to read them on your mobile, too.
The downside is that Outlooks on other PCs will poll them too. Even if they already received them from a sync, thus causing duplicates. (The problem here is Outlook, not Easy2Sync!)
Easy2Sync for Outlook has 2 strategies to solve this. They can be activated in the properties of the task. (The checkboxes are only available if the program detected that you use this Outlook-option.)
Solution #1: Fix Outlook-duplicates
If you use this option, duplicates will still be created, but EasySync for Outlook Outlook will fix them automatically during the next sync.
However, this does not work if you:
|•||Delete an e-mail permanently|
|•||Delete an e-mail in the Deleted items folder and empty that folder|
|•||Move an e-mail another another data storage|
This options makes the sync slightly slower. (If you have a very large number of e-mails with identical subject / sender, the merging phase can take quite long.)
Solution #2: Prevent Outlook-duplicates
To solve this, Easy2Sync for Outlook can sync the e-mail poll information. Then Easy2Sync will tell the other PC during the sync which messages were already downloaded. This sounds good, but need need to work in a certain order:
|1.||Run the sync|
|2.||Now (re)start Outlook on the other PC|
|3.||Now poll the e-mails on the other computer|
(Sorry, the order and the Outlook restart are caused by the Outlook internals.)