Mozilla Mailnews FAQ

How can I use more than one identity on one account?

Even though it is not implmented in the user interface, it is possible to set up more than one identity for one account. This is done through editing the prefs.js.

Open up prefs.js in your favorite text editor. Look for a set of identity prefs with the following form:

"mail.identity.idX."

where 'X' is a number like 1, 2, 3, etc. Pick the set of identity prefs which are already associated with the account you want to add a new identity to and make a copy of all the prefs that are prefixed with the identity you picked (i.e. "mail.identity.id1"). Change the number to the next available integer. Make sure you are not using an integer that is already used by another set of identity preferences.

Tweak the settings for this new identity according to taste. You may not need to change many of these settings from the one you copied. In particular, don't forget to change the .useremail attribute to the email address associated with this identity. You should now have a new identity that is not attached to an account yet that looks similar to the following (remember id# is really id followed by an unused integer chosen by you)

user_pref("mail.identity.id#.doBcc", false);
user_pref("mail.identity.id#.doBccList", "");
user_pref("mail.identity.id#.draft_folder", "SOME URL YOU DON'T NEED TO CHANGE");
user_pref("mail.identity.id#.drafts_folder_picker_mode", "0");
user_pref("mail.identity.id#.encryption_cert_name", "");
user_pref("mail.identity.id#.encryptionpolicy", 0);
user_pref("mail.identity.id#.fcc_folder", "SOME URL YOU DON'T NEED TO CHANGE");
user_pref("mail.identity.id#.fcc_folder_picker_mode", "0");
user_pref("mail.identity.id#.fullName", "YOUR NAME");
user_pref("mail.identity.id#.organization", "YOUR ORGANIZATION");
user_pref("mail.identity.id#.overrideGlobal_Pref", true);
user_pref("mail.identity.id#.reply_to", "");
user_pref("mail.identity.id#.sign_mail", false);
user_pref("mail.identity.id#.signing_cert_name", "");
user_pref("mail.identity.id#.smtpServer", "smtp1");
user_pref("mail.identity.id#.stationery_folder", "SOME URL YOU DON'T NEED TO CHANGE");
user_pref("mail.identity.id#.tmpl_folder_picker_mode", "0");
user_pref("mail.identity.id#.useremail", "SOME EMAIL ADDRESS");
user_pref("mail.identity.id#.valid", true);

Now that you have created an identity, you need to bind it to an account so it shows up as one of the multiple identities for that account. Find the account you want to add the identity to. It should have the following form:

mail.account.account#

where '#' is an integer. Be sure to find the right account. Now modify the .identities preference for that account, appending the new identity we just created after the default identity for the account. You can append as many identities as you want / have created.

user_pref("mail.account.account##.identities", "id1,id#"); where id# is the number of the new identity

Now save prefs.js and launch Mozilla. Bring up a compose window. If you set everything up correctly you should see the email address for this new account listed in the From: drop down box. Reply to a message which was sent to the email address used by your new identity. You should see it get pre-selected in the from field.