W3wp high CPU usage in Exchange Server 2013

Applies to: Exchange Server 2013 EnterpriseExchange Server 2013 Service Pack 1Exchange Server 2013 Standard Edition

Symptoms


In a Microsoft Exchange Server 2013 environment, Exchange servers may experience the high CPU usage issue and the IIS worker process (w3wp.exe) consumes lots of CPU utilization, which is the MSExchangeMapiMailboxAppPool application pool. As a result, either you cannot connect to the Exchange Server 2013 servers or the Outlook client freezes.

Cause


This issue occurs because MSExchangeMapiMailboxAppPool is waiting for a global lock inside of system timer queue.

Resolution


To fix this issue, install Cumulative Update 19 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

References


Learn about the terminology that Microsoft uses to describe software updates.