No notification when message arrives

[tshad]

I have Outlook 2000 installed on most of our machines at the office and all
have "Display notification message when new mail arrives" checked in the
email options/Message handling screen.

Most of the machines work fine. As soon as exchange recieves a message
outlook is notified and we get a popup saying a message has arrived.

But a couple machines don't get the message. They just have to touch the
outlook window (recieved column header, Send/Recieve etc) and the message
shows up.

What would cause this behavior?

Thanks,

Tom