Comment 12 for bug 35212

I am also seeing this on Mac OS X, Mozilla 2003011408.

In my case, creating a new profile and immediately creating a mail message works
(prior to setting up mail accounts; this also prompts the setup wizard). As soon
as I configure my mail account (using IMAP, but I have not tried POP) I get the
error message.

Moreover the alert box has no focus and clicking on it does not bring it into
focus so you cannot dismiss it. Switching to another window or application and
then switching to the alert box will bring it into focus (during that time there
is a "compose" item listed under the window menu along with an item with no
name. Choosing the compose item brings the alert into focus.