Exchange 2013, CU6,

Passive database in DR site faced the Service down because of network issue and was automatically recovered by Exchange self diagnostics.

I rememeber that it needs to be manually take service-up in Exchange 2010, EMC in that case.

What is the functionality of Microsoft Exchange Diagnostics?

Event logs

Microsoft Exchange Diagnostics service terminated unexpectedly, restart service

• Edited by tanale Friday, May 01, 2015 2:43 AM

Hi tanale,

Thank you for your question.

What is the functionality of Microsoft Exchange Diagnostics?

A: Microsoft Exchange Diagnostics is agent which monitors server health.

With the event log, we could refer to the following steps to fix it:

1.        Kindly delete both keys from Registry ExchangeDiagnosticsDailyPerformanceLog & ExchangeDiagnosticsPerformanceLog
2.        Ensure Template is available in the following location :HKLM\Software\Microsoft\PLA\Templates
3.        Delete Counter in the following path: Perfmon ->DataCollector->User Define -> Delete ExchangeDiagnosticsDailyPerformanceLog counter.
4.        Restart the Exchange server to check if the issue persist

Notice: We can just delete both ExchangeDiagnosticsDailyPerformanceLog and ExchangeDiagnosticsPerformanceLog entries from the above registry location and then reboot server. After rebooting server, the new default ExchangeDiagnosticsDailyPerformanceLog will be recreated automatically in the task scheduler and performance monitor.

The more details could be referred by the following link:

http://blogs.technet.com/b/anya/archive/2014/11/25/microsoft-exchange-diagnostics-service-crashing-post-cu6-upgrade.aspx

If there are any questions regarding this issue, please be free to let me know. 

Best Regard,