According to some user reports 
, it looks like Gmail Notifier is no longer correctly reporting new mail in Gmail accounts.
Neither the old version or the recently updated one are working for me.
If notification is important to you, it might be worth switching to GmailStatus (which is working fine) until the problem is sorted out.
UPDATE: The crisis must be over. Gmail Notifier just sputtered into life again.
[...] Gmail notifier problem has been blogged. [...]
I notice that the Gmail dashboard widget from Google is also not working.
GmailStatus doesn’t seem to be working for me either. Both are down. I would assume all these notifiers are drawing from the same data.
That’s weird. GmailStatus is working fine for me just now.
I use GMail Checker (http://www.apple.com/downloads/dashboard/email_messaging/gmailchecker.html) — also not updating. I’ve found that both that one and the official Google widget don’t update for me, but clicking on them will go to the website and log me in OK — so it’s not a change in the login procedure.
The problem has to do with Gmail’s Atom feed (http://mail.google.com/mail/feed/atom) which is currently not working correctly. I’ve heard the Gmail folks are working to fix it and it should be fixed shortly.
[...] I thought it might have been just me, but Hawk Wings says that some people are reporting issues with the latest version of Google’s Gmail Notifier. [...]