“Computer Monitoring Error” on Dashboard or Launchpad

“Computer Monitoring Error” on Dashboard or Launchpad

Technical Background:
This issue applies to the following products:
Windows Small Business Server 2011 Essentials, Windows Storage Server 2008 R2 Essentials and Windows Home Server 2011.
The “Alert Evaluation Component” is a component that evaluates the system status against a set of pre-defined rules, and then reports the result to health monitor.
This evaluation is triggered every 30 minutes, rules are under %Programfiles%/Windows Server/Bin/FeatureDefinitions/ on the server and client.
When evaluation fails, the system will throw the "Computer Monitoring Error" warning.

This article provides quick workaround for two known issues that triggered this alert, further resolution and additional cases are still under investigation.

Root Cause:
There are several reasons Alert service will generate “Computer Monitoring Error”, including:

Client or Server are missing Powershell execution engine.
2. An alert evaluation component throws unhandled Exception. (That’s the most common cause we have seen)
3. An alert evaluation component can’t find its Feature Definition file that includes the evaluation rules.
4. An alert evaluation component does not report results after a certain time.
When these situation happen, those alerts evaluated by that component will never show up. But other alerts or product features will not be impacted.

This warning could be generated by different reasons, the following sections are already known issues caused “Computer Monitoring Error”.

“Computer Monitoring Error” shows on the Server after updated with Update Rollup 2.

Update, a hotfix is avaialbe for fixing this issue, please check following KB articles for download links

You receive the warning "Computer Monitoring Error" in Windows Storage Server 2008 R2 Essentials after you install Update Rollup 2:
You receive the warning "Computer Monitoring Error" in Windows Home Server 2011 after you install Update Rollup 2:
You receive the warning "Computer Monitoring Error" in Windows Small Business Server 2011 Essentials after you install Update Rollup 2:

This happened after the system installs Update Rollup 2. You will find the following exceptions in the SharedServiceHost-AlertServiceConfig.log file under %Programdata%\Microsoft\Windows Server\Logs.

120222.003152.9814: NetworkHealthEngine: Exception happened in Microsoft.WindowsServerSolutions.NetworkHealth.Engine.BinaryActionDefinition: System.NullReferenceException: Object reference not set to an instance of an object. at Microsoft.WindowsServerSolutions.Servicing.Alerts.MacClientUpdateCondition.Run(IActionContext context)

It is caused by one of the Alert evaluation components – ServicingAlerts.dll, when it tries to evaluate whether there are Mac clients in the network.
It will throw an exception when some machine returns "unknown" for the OS version. It could happen when you have a machine that is disconnected from the server.

You will never see that warning reminding you to update your Mac client connector.
If you don't have a Mac client, this alert will not show up anyway, so you can assume this alert is a false alarm.
No impact to other alerts or product features.

1. Select any client computer in the “Computers and Backup” tab on the dashboard.
2. Check the “Operation System” value in the “General information about this computer” area on the bottom.
3. If the value is unknown, right click the client computer and select “Remove the computer”.
Note, If you see the clients are in the "Archived computer backups" category, please be aware that if you remove the computer, it will also remove all backups for that client.

“Computer Monitoring Error” shows on the Client after Server installed BPA.

This only applies to machine that installed WSSG 2011 BPA. You will find following Exception in the SharedServiceHost-ClientAlertServiceConfig.log file under %Programdata%\Microsoft\Windows Server\Logs on the client.

[2216] 120223.103228.7431: AlertFramework: Subcomponent: HealthEvaluator > Condition Evaluation for HealthDefinitionName=BPAChecker_Scan FeatureName=WSSGBPA threw an  exception: Microsoft.WindowsServerSolutions.NetworkHealth.Engine.ActionRuntimeException: You cannot call a method on a null-valued expression. ---> System.Management.Automation.RuntimeException: You cannot call a method on a null-valued expression.

It is caused by the BPA Alert evaluation component. This alert evaluation is designed for server only.
When it is running the client, it cannot find proper BPA files, and throw an exception instead exit silently.

You will see a “Computer Monitoring Error” on the client, there is no impact to BPA functionalities, as BPA will not run on client.
BPA alerts on Server, other alerts or production features are not impacted.



Uninstall BPA on the server
2. Install BPA on the server again,  do NOT select the check box “Integrate Windows Server Solutions BPA scan results in the server console.” Be aware that you will not see  BPA scan results in the server console after this. You can still open BPA UI to see the result.


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  • Please note that Support is still working on a fix.  These alerts cannot be ignored as they stand.  They return every 30 minutes.  I have two archived backups from removed workstations that are causing this error.  This wiki explains the alert error, it is not the fix.

  • Thanks, Susan, this article provides quick workaround for the known issues that triggered this alert, further resolution are still under investigation.

  • This has started happening on my WHS 2001 system as well.  It's getting very annoying. I do not have any of the symptoms described.  I'm not sure but it may have started once I upgraded one of my clients to Win8.

  • Yep, I too am now getting this error. Microsoft, let's have a fix please. We've been patiently waiting for quite a while now.

  • Can everyone on this thread email me at susan-at-msmvps.com so I can make sure your log files get examined?

  • @tbar .... Hmm, you might be onto something. These errors started after I upgraded a few PCs to Win8CP.

  • I just installed WHS 2011 and have this alert.  I do not have any Win8 clients but i do have a Mac client running the Lion OS.  The connector did not completely install on my mac due to the other issue where launchpad is named the same as the Mac launchpad.  I will try the workaround for the unknown OS and see if that resolves the issue.

  • I started getting this alert after recently removing a workstation while keeping archived backups.

  • I have this same issue, which started after I added a Win8 machine. The weird thing is, I formatted, and reloaded my entire server, added my 2 Win7 boxes, and the error came back even without adding The Win8 machine.

  • I also am getting this error message.  It started after a re-install of WHS 2011 to address the wrong WORGROUP name issue.  This issue is resolved thanks to an article in WeGotServered web-site.  I had a DriveBender pool from the previous setup that I revived using the DriveBender tools.  This is working correctly but is still rebuilding the pool.  I have a lot of duplciaiton of folders in the pool so this process will take some time.  I have one MAC OSX client running Lion.  The connector for the MAC client installed correctly with no issues.  All client computers are known with no unkown entries.  

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