I am currently on 10.8.2 and have been using Mail as my email client without a problem since I started using Mountain Lion. My primary email account was a gmail account, however, recently I added 2 additional gmail accounts to Mail so I could use a single program to manage all of my email accounts. This was working fine, until Mail stopped sending emails from my primary account. Whenever I try to send an email using my primary email account, it uses another one of my gmail accounts instead. As you can imagine, this is extremely annoying. I can receive emails fine, and when using 3rd party programs (like sending something via Evernote), it's sent from my primary account without an issue. I looked in the preferences for Mail, and noticed that the outgoing mail server was set on "Gmail (Offline)". I thought this was the problem, and switched it over to one of the other outgoing gmail options, but this has not fixed the problem. I also have tried deleting and reinstating the account in mail, but the problem still persists (by default, it goes to "gmail (offline)). Does anyone have any idea on what I can do to fix this? Thanks in advance to anyone who can help.