On servers that are running Microsoft Exchange Server 2016 and that have Cumulative Update 4 or Cumulative Update 5 installed, you experience the following situations:

  • The Microsoft Exchange RPC Client Access service process (Microsoft.Exchange.RpcClientAccess.Server.exe) consumes excessive CPU resources on Exchange Server 2016-based servers.

  • A memory leak occurs in the Microsoft Exchange RPC Client Access service on Exchange Server 2016-based servers.

  • The Exchange application pools (EWS, RPC, MAPI, ActiveSync) on Exchange Server 2016-based servers experience high CPU usage and a memory leak.

Note If you have installed third-party email archiving software on Exchange Server 2016-based servers, this issue might be worsened.


To fix this issue, install cumulative Update 6 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.


To work around this issue, restart the service or application pool to temporarily fix the issue.

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.


Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

What affected your experience?

Any additional feedback? (Optional)

Thank you for your feedback!