Resource Booking Assistant crashes after you upgrade to Exchange Server 2013 Cumulative Update 5

Applies to: Exchange Server 2013 EnterpriseExchange Server 2013 Standard Edition


After you upgrade to Cumulative Update 5 for Microsoft Exchange Server 2013, the Resource Booking Assistant (RBA) crashes at two gigabytes (GB), and it cannot process on the resource room to accept the message on the mailbox.


This issue occurs because too many instances of the Calendar Repair Assistant (CRA) are running on the server. This causes RBA to hit the memory limit and therefore crashes.


To resolve this issue, install Cumulative Update 7 for Exchange Server 2013.


To work around this issue, follow the instructions to limit the number of concurrent CRA threads to no more than five: 
  • Under the Exchange installation path \Bin folder, open the MSExchangeMailboxAssistants.exe.config file.
  • Add the following key under the appsettings node:
    <add key="Workload.CalendarRepairAssistant.MaxConcurrency" value="5"/>
  • Restart the Microsoft Exchange Mailbox Assistants service (MSExchangeMailboxAssistants).


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