Extension Microsoft Outlook adds to saved email, Eudora mailboxes
MBX is an email extension file format created by Microsoft Outlook Express. Outlook stores message data in MBX files on the user’s computer. MBX files are usually held in a folder that corresponds to a folder within Outlook, such as Inbox or Sent. The folders also have the .MBX extension.
Learn more about .MBX files:
Read more about Outlook Express on Wikipedia.
Search for .MBX-related questions on IT Knowledge Exchange.