Having had this problem in previous versions of Service Desk, never having it resolved by support and following an upgrade to 7.4 with the problem remaining I turn to the you, the greater popultation for a possible solution.
LSSD Ver: 18.104.22.1689
Background: We use Unity for our voicemail and when ever someone leaves a voicmail for the service desk Unity emails the service desk mailbox and attaches a wav file.
Problem: Mailmanager does not read and log an incident for these voicemail messages. The only way I can get it to read them is to forward the mail to the service desk again. They are then logged and the wav file attached to the incident.
Solution: Over to you guys n gals.