Email "from" is not using Default account My email replies default to my Gmail account even though the "from" line and the "default account" in the Settings are my main (preferred) account address. How do I fix this?
It's a known bug introduced in Mountain Lion and was submitted to Apple by several people.
Mail ignores the Send new messages from: Account of selected mailbox setting.

See for example:


https://discussions.apple.com/thread/4148125?start=0&amp;tstart=0
http://forums.macrumors.com/showthread.php?t=1414206
http://mjtsai.com/blog/2012/08/03/mail-mountain-lion-reply-account/


I submitted the bug and is now marked as duplicate (but Apple's reporting tool does not allow you to see the duplicated entry).