In most cases, if other applications open when clicking a MSG file, this is because MSG Viewer for Outlook is not configured to be the default application when opening MSG files.

Using the Preferences menu item (OS X 10.8+) or by double-clicking the MSG Viewer for Outlook application (OS X 10.6-10.7), you can set MSG Viewer for Outlook to the default application.

You can also get around this issue by right-clicking on an MSG file and choosing "Open With → MSG Viewer for Outlook". Alternatively, please visit this link to learn how to change the default file associations on your Mac.

In some cases, Parallels Desktop may also be overriding the file association to open the MSG file in Windows, see this link for additional help on changing those settings.

If you have multiple versions of an application installed (e.g., multiple versions of Microsoft Outlook installed on the same machine), and the wrong version of the application is opening, please do the following:

  1. Close all instances of the application (e.g., Microsoft Outlook)
  2. From your Applications folder, double-click the desired version you wish you open.
  3. Close all instances of the application (e.g., Microsoft Outlook).

This issue should be resolved and this technique can be used any time the wrong version of the application is used.

If the problem only happens when clicking an EML file, this is because your default Mail client on your Mac is set up differently than you would like. Please visit this link.

Pro tip: If these tips don't work, you may need to reboot your computer or empty the Trash to delete any older copies of Outlook MSG Viewer of MSG Viewer for Outlook that may be interfering. Please also confirm that your default email client is set up correctly in the "Customizing MSG Viewer for Outlook" section above. It is possible that the MSG file is converting properly, but a working email or address book client has not been properly configured.