When importing E-mails from Windows Live Mail eM Client created (during installation) a copies of most of the E-mails in WML. Message which was duplicated is marked as “UNREAD”. Original message is listed in the window pane but not available for viewing - it displays Message cannot be found Some messages got duplicated twice.
I now have over 64000 new messages in the main account INBOX. The messages in it were going back to 2013. Duplicated messages are not appearing twice in eM Client.
If the account was setup as IMAP in WLM, there is no need to import the messages.
All you need to do is setup the same email account in eM Client, and the messages will automatically sync from the server.