Is this appearing while setting up or long after setting up your Gmail account in Mail? If the former, be sure to follow Google's setup instruction to uncheck the Mail account setup checkbox that tries to automatically setup an account based on your address. Then ensure your intention is to set up a POP account for Gmail instead of IMAP. Only the latter will keep your account in sync with Gmail's Web-based system.
Thanks so much for being there.
I'm not married to POP, I'll go IMAP if I can be rid of those d...ed pop-ups. Is there something about IMAP I should be wary of since my entire experience has be POP mail?
Does Google have good attentions with this POP/IMAP stuff?
I don't know what your latter question about Google means. You should not delete your POP account right away in case any messages you need have been removed from Gmail's server. You should simply add your Gmail account as IMAP and ensure all your mail is present before deleting anything. First, though, be sure IMAP is enabled in Gmail Settings and read the setup instructions there.
My question about Google had to do with my perceived view that in the service of its own interests, Google seems to be foisting IMAP on all its users. I'm simply trying to determine whether my interests are served any better also.
Yes, Google agrees with the techies among us who believe that IMAP is better than POP. When you receive email with POP, your replies, forwards, deletions, etc. are all stored only on your computer and not synchronized to the server, so if you log into Gmail on the Web, you'll see your inbox untouched.
IMAP is the Internet-based alternative where everything is synchronized and no changes remain unaccounted.