There is a known problem when exporting the Windows Address Book (*.wab) files to another PC. If the user has contacts organized into folders, this folder structure will not be preserved when the WAB file is imported. All contacts will be preserved, however, leaving some with a considerable task of manually reconstructing the folders and moving addresses back into their rightful places. See: http://support.microsoft.com/kb/249670
A solution for Windows versions still using WAB files as their address book is to copy, not export/import, the WAB files to their correct location. This often preserves the folder structure. Unfortunately, in Windows Live Mail this does not work as WLM doesn't use WAB.
Making your Windows Live Contacts work with Windows Contacts http://windowsvistablog.com/blogs/windowsexperience/archive/2007/05/13/making-your-windows-live-contacts-work-with-windows-contacts.aspx ↩
Windows Contacts Schema Overview http://msdn2.microsoft.com/en-us/library/ms735869.aspx ↩
Programming Windows Contacts http://msdn2.microsoft.com/en-us/library/ms735866.aspx ↩