Microsoft has released an important update for customers who have deployed Cumulative Update 6 for Exchange Server 2013 in a co-existence environment with Exchange Server 2007.
Support article KB2997209 is titled Exchange Server 2013 databases unexpectedly fail over in a co-existence environment with Exchange Server 2007, which is a pretty good description of the issue that customers are experiencing.
The problem occurs when an Exchange 2007 mailbox user tries to access a delegated mailbox that is hosted on Exchange 2013 CU6. The Exchange 2013 CU6 server’s attempt to authenticate the connection causes the Store process to crash, which in a database availability group will result in a database failover to another DAG member.
The available hotfix can be obtained by contacting Microsoft Support. More details are available here.
This article Important Update for Database Crashes in an Exchange Server 2013 Cumulative Update 6 and Exchange Server 2007 Co-Existence Environment is © 2014 ExchangeServerPro.com
Get more Exchange Server tips at ExchangeServerPro.com
