Follow the given steps to disable the email notification option:
To edit the computer registry, first you should log onto your computer with administrative rights.
First click on Start button and type "Regedit" in Run option.Here locate the location to:
Navigate to HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows \ CurrentVersion \ UnreadMail
But if MessageExpiryDays key doesn't exist, then in right side panel, click right to create a key with the nameMessageExpiryDays and then set its value to 0.
Now close the registry editor and restart your computer after any changes to go into effect.