Greetings! As you are going into production, hopefully you allocate a few days for exception sweep up. This is applicable to any website running on Sitecore CMS

One of the common exceptions that I see in customer’s log files these days is related to “alarm clock” event subscriber and can be encountered quite frequently.

Here is the error stack trace that you may be seeing in your logs:

ERROR Exception in alarm clock event subscriber.
Exception: System.Reflection.TargetInvocationException
Message: Exception has been thrown by the target of an invocation.
Source: mscorlib
   at System.RuntimeMethodHandle.
InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)    at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)    at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)    at Sitecore.Reflection.ReflectionUtil.InvokeMethod(MethodInfo method, Object[] parameters, Object obj)    at Sitecore.Configuration.Factory.AssignProperties(Object obj, Object[] properties)    at Sitecore.Configuration.Factory.AssignProperties(XmlNode configNode, String[] parameters, Object obj, Boolean assert, Boolean deferred, IFactoryHelper helper)    at Sitecore.Configuration.Factory.CreateObject(XmlNode configNode, String[] parameters, Boolean assert, IFactoryHelper helper)    at Sitecore.Pipelines.CorePipelineFactory.GetObjectFromType(String type, XmlNode processorNode)    at Sitecore.Pipelines.CoreProcessor.GetMethod(Object[] parameters)    at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)    at Sitecore.Services.AlarmClock.HeartbeatBeat(Object sender, EventArgs e)

_Nested Exception _

Exception: System.InvalidOperationException
Message: Category does not exist.
Source: System
   at System.Diagnostics.PerformanceCounterLib.GetCategorySample(String machine, String category)    at System.Diagnostics.PerformanceCounterCategory.GetCounterInstances(String categoryName, String machineName)    at Sitecore.Diagnostics.PerformanceCounters.PerformanceCounter.GetInstanceName()    at Sitecore.Pipelines.HealthMonitor.HealthMonitor.AddCounter(XmlNode configNode)

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After a quick research in our knowledge base, I’ve discovered an answer. Apparently, this has been addressed in Sitecore CMS 6.2.0 rev.100104 (Also known as 6.2.0 Update-1).

For 6.0/6.1 instances, you can comment out the following part of your web.config file as a temporary workaround:

<processor type="Sitecore.Pipelines.HealthMonitor.HealthMonitor, Sitecore.Kernel" method="LogCounterStatus">
 <counters hint="raw:AddCounter">
 <!-- <counter category="Process" name="Private Bytes" />  
 <counter category="Process" name="Virtual Bytes" />  
 <counter category="Process" name="Page File Bytes" />  
 <counter category=".net CLR Memory" name="# Bytes in all Heaps" />  
 <counter category=".net CLR Memory" name="% Time in GC" />  
 <counter category=".net CLR Memory" name="Large Object Heap size" />  
 <counter category=".net CLR Loading" name="Bytes in Loader Heap" />  
 <counter category=".net CLR Loading" name="Current Assemblies" />-->  
 </counters>  
</processor>

If you are still on 6.0 or 6.1, start thinking about upgrading. It is especially easy to do it from 6.1! Check the official steps here