Why is the Clients with RPC Latency > 2 secs counter showing a very high number in the Diagnostic Console?
This counter is populated by thePerformance Counter on the target Exchange Server - MSExchangeIS Performance Object | Client: Latency > 2 sec RPCs Counter.
This counter can become corrupted.
To troubleshoot this issue open Perfmon from the Spotlight server and connect to the Performance Object and verify the same information is being reported.
On the Spotlight server:
1) Start - Run - Type Perfmon
2) When Perfmon has opened - Click the + button on the tool bar
3) In the first dropdown type the name of the target Exchange Server preceded by \
4) In the second dropdown select MSExchangeIS Performance Object
5) Then find and select Client: Latency > 2 sec RPCs from the counters list
6) Click Add
Review the output, this will be exactly the same as the figure reported by Spotlight or very close depending on the refresh period selected in Spotlight.
Review Microsoft Tech Net Articles and determine the issue with Exchange that has caused Perfmon to report these large numbers.