From: DeskNow Knowledge Base
http://www.desknow.com/kb/

All the new emails that I receive are already marked as read before I see them
http://www.desknow.com/kb/idx/4/108/article/

This could have different causes:

POP3 client

You have a pop3 client downloading mail periodically from your account. Mail downloaded by a POP3 client (and left on the server) is automatically marked as read. You can change this behaviour by changing the property EmbeddedServer.SynchronizeWebmailWithPOP3Read

to FALSE

in Mail.cfg and restarting DeskNow

Mail filter

You have a mail filter that operates on incoming emails, whose action is 'mark message as read'.