Assume that lots of users synchronize their mailboxes in a Microsoft Exchange Server 2010 environment by using Apple devices such as iPhone or iPad. These Apple devices are running iOS 5.0 or iOS 6.0, or a later version than iOS 5.0 or iOS 6.0. In this situation, high CPU usage (about 80 to 100 percent) occurs on the Client Access server (CAS). Then, the synchronizations fail, and the users cannot receive new email messages.
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