Event ID 2142 when Exchange services don't start
Original KB number: 3090811
Symptom
When you try to start Exchange services, the services don't start, and the following event is logged in the Application log:
Log Name: Application
Source: MSExchangeADTopology
Date: 3/18/2016 4:15:00 PM
Event ID: 2142
Task Category: Topology
Level: Error
Keywords: Classic
User: N/A
Computer: EXCH2013.contoso.com
Description:
Process Microsoft.Exchange.Directory.TopologyService.exe (PID=1376) Forest contoso.com. Topology discovery failed, error details
No Minimal Required Number of Suitable Directory Servers Found in Forest contoso.com Site Default-First-Site-Name and connected Sites..
Cause
This issue may occur if the total number of available domain controllers across multiple Active Directory sites is less than the MinSuitableServer value (the default value is 3).
Resolution
To resolve this issue, restore the number of available domain controllers to a number equal to or greater than the MinSuitableServer value.