How to upload MSG file to IMAP Server for Mac? Use the latest Mac MSG Importer wizard, it helps you to add or upload MSG file to IMAP Server for Mac all along with complete MSG files Meta details, attachment files, images, etc. You can also upload multiple MSG files to IMAP Server for Mac with the help of latest Mac MSG Importer wizard in one go. Download the latest free Mac MSG Importer software to test its working functionality, it supports 20+ files at a time.