Leave a copy of email on the server - Windows Live Mail

Going to "Tools"
-> "Accounts" which will bring up the "Accounts" pop up window.

Click on the account for which you want to change the settings
and then hit the "Properties" button

Select the last one - the "Advanced" tab -
checkmark in "Leave a copy of messages on server".

You can set number of days or when you delete them from the Deleted Items folder.

Click button
then click button.