This problem still has not been fixed and I can't help but say it's a catastrophe. Very very disappointed with Apple's complete disregard to date for this major dysfunctionality affecting confidentiality in Mavericks Mail.
The problem is simple - if you're foolish enough to save a draft mail message, then an undisclosed recipient list DOES NOT STAY UNDISCLOSED. Instead, the addresses are all displayed, even though the settings for an Undisclosed list are correct (see below). It all worked fine prior to Mavericks. Now - it's bust.
For a group address, choose Mail > Preferences, click Composing, then deselect “When sending to a group, show all member addresses.”Recipients see “Undisclosed-recipients” in the To field.
And yes, thanks jimbo60640, we can use Bcc as an alternative, but that's a poor substitute for the real thing which STILL DOES NOT WORK AS DESCRIBED and does not work as it did under OS X.
I'm new to Apple/iMac/Mail/OS X/ Mavericks. How on earth do we get this feedbck to Apple and get them to fix this??? Anyone?
Mavericks by name; Mavericks by nature.
Stack of other problems with Mavericks that also haven't been fixed. Crash test dummies it would seem.