How is it best to migrate from Entourage to Outlook 2016 when upgrading to El Capitan?
Emailchemy
What is the best way to archive some of my 250,000 emails prior to migrating to a new Mac?
Someone sent me an enormous file, 49 MB in size, of Zipped-up .msg files. How can I access these?
Most common problems are failure to collect or send, but this gives you clues to solving many other problems such as stuck messages.
The Eclectic Light Company 