Recently had an ungraceful shutdown of a PI System. When it came back up the Performance Counters for all the PI Services had disappeared and subsequently the PI Perfmon tags had stopped updating (no errors in the log files!!!). Anyway, turns out that Windows perflib decided to disable all the PI Services counters by setting the "Disable Performance Counters" DWORD on each of them.
Anyone have any idea why, or what perflib logic is for disabling the performance counters? Seems the ungraceful shutdown upset perflib somehow...all other non-PI performance counters were still available.