Choose the EML files

Choose Add Emails in the toolbar or File > Add Email Messages, select one or more .eml files, and choose Add. MBox Office validates that each selection looks like an email before changing the archive.

Let the mailbox reopen

Each EML is appended as a new message. If the operation cannot finish, MBox Office leaves the mailbox as it was whenever possible. The mailbox then reopens to show the added messages.

Protect an irreplaceable archive

Keep a backup before modifying an important archive, avoid changing the same file in another app at the same time, and make sure the Mac has enough free disk space.