Import/Export from Windows Mail to Windows Mail

We have one system that everyone uses(Multiple login ID's). When we purchase laptops we want to move all mail files from the desktop to the laptop. When I export the messages and try to import them to the laptop, I only get about half of them. I see all of the directories listed during the import, but only half show up. What am I missing here? I moved 12 users from Outlook Express to Windows Mail with no problems. I have to be missing a step or something.

Thanks for the help.