File Extension SEML File Format Sealed E- mail ( SealedMedia ) SEML stands for Sealed E- mail ( SealedMedia ). This was last updated in March 2012 By Margaret Rouse Browse File Extensions Alphabetically: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # Ask a Question. Find an Answer. Ask your peers a question about this file extension. Ask a Question Lotus notes 8.5.3 Server - Want to hold outgoing mail in mail.box - stop delivery Open a new email dialog using API secondary external e-mail address to my MS Outlook 2003 inbox?