In Yahoo! Messenger 9, you can do the following to remove the notice when you receive new mail:

1. On the Menu bar, go to Messenger – Preferences. (Or just press Ctrl+Shift+P to open the Yahoo! Messenger Preferences window.)
2. Under the Category selection, choose Alerts & Sounds.
3. Under "Alert me when," choose "I receive a message in Yahoo! Mail."
4. Under "Alert me by," uncheck "Showing a message at the right bottom corner of my screen."

Note: If the Message Preview you are referring to gives you options to press either "Go to Yahoo! Mail" or "OK" and you want to disable this, also uncheck "Displaying a dialog box" still under "Alert me by."

Optional: You might also want to remove the other alert options ("Playing a sound" and "Showing an icon on the system tray").

The notice (or dialog box) showing the sender and the subject should no longer appear when new mail is received while using Yahoo! Messenger.

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