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KB04258-How to remove an integrated email address from the BlackBerry Internet Service
Overview
The BlackBerry smartphone is receiving duplicate email messages from one or more Yahoo!® Mail accounts.
Environment
BlackBerry® Internet Service
BlackBerry smartphones
Cause
One of the Yahoo! Mail accounts is the original account and the others are aliases of the original. Since they are aliases, they share the same inbox on the Yahoo!® messaging server. This means that the same inbox is checked multiple times and the same email messages will delivered for each alias.
Resolution
Remove all but one of the Yahoo! Mail accounts.