I ran into a situation the other day with a customer who wanted to change his email client from Entourage 2004 to Apple Mail. My customer runs a small business and has over 15,000 messages saved on his computer. In the process of converting his email, he noticed that several hundred messages from his Sent folder did not transfer over. Rather than run Mail.app’s import function a second time, I opted for a simpler solution using recommendations found on the Apple Discussion Forum.
Apple Support Discussions: Mac OS X v10.5 Mail and Address Book
Topic: Entourage to Mail migration
“For Entourage calendar and contacts, just sync to iCal and Address Book. Go into Entourage Prefs, Sync, and enable sync. Then, after they show up, go back into Prefs and turn off sync.”
“For email, you can drag Entourage folders (bottom level folders) onto your Desktop, and they become single .mbox files (one file per folder) containing all the messages and attachments.”
To facilitate the mbox conversion, I created a new Sent folder in Entourage that contained only the messages that failed to transfer.
“You can then import those mailbox files using Mail’s File menu.”