Noticed this in the "Miscellaneous behavior changes in FileMaker Pro 12" document (http://help.filemaker.com/app/answers/detail/a_id/10084/):
The following email clients are no longer supported, and the code that interacts with them have been deleted:
Microsoft Outlook Express
Qualcomm Eudora 6.x
The following email clients are still supported:
Windows: Microsoft Outlook (Microsoft Outlook 2011 is now supported), Outlook Express, or Eudora
Mac OS X: Entourage, AppleMail, or Eudora
...so is Outlook Express still supported or not? How about Eudora? 6.2.4 is the last Mac Eudora version, but it specifically says "Eudora 6.x" in the "no longer supported" list.