email move function acts like copy

When I select a group of messages in a folder and select a folder to move them to and click move, the server appears to copy those messages instead of moving them. They appear in the target location but remain in the source. I've tested this on multiple mailboxes and folders within those mailboxes. Delete works so I am instructing my users to move and then reselect and then delete.. I only have a couple of people doing even THAT .. and it's Thanksgiving day.. henceforth the Medium severity level chosen. :-)

Regards.