There is a limit to the lengths of recorded messages that L*E*O can store. You can see what this length is by choosing Message Setup from the Setup menu. For example, if L*E*O is configured for 12 cards, the length of a message for each cell can be up to 5.4 seconds at highest quality if you are not allocating time for previews (available only in the scanning model). Thus, for example, you will not be able to record the entire "Happy Birthday" song on a cell. (You could, however, split the song into sections, and record each phrase to a different cell.) You can crop a message using the Record Message / Preview dialog so that the message ends within the allotted message time.