I have this with a few emails accounts going into it.
In my "Unread Items", emails for one of my email accounts seem to come through in duplicate/triplicate which clutters up the inbox when I'm trying to read through, especially in getting rid of spam as one of the email addresses is an older one and gets a lot of spam email.
I've had a look round the settings and it only has the email addresses once (initially thought I'd maybe entered it more than once by accident).
Has anyone come across this and knows a fix for it?
You could try a repair on it and see if it fixes it. Go to Control Panel , All Programs scroll down to Windows Live Essentials Right click on it click change and then Repair and let it do its bit. It is worth a try .
Have you more than one Anti Virus Programme. I understand that having two AV programmes can cause duplication, triplication, and even more; up to hundreds have been claimed.
Another thought is that you have a Server problem which is not connected with your Windows Live Mail and should be referred to the Server.