Submit a ticketCall us

Systems Monitoring for Dummies
Our new eBook will teach you the fundamentals and help you create monitors and alerts that are effective, meaningful, and actionable. Monitoring is more than a checkbox on your to-do list. This free eBook will give you practical advice to help you succeed in all aspects of monitoring – discovery, alerting, remediation, and troubleshooting. Don’t miss out on this indispensable resource for newbies, experienced IT pros, and everyone in between. Register Now.

Home > Success Center > Server & Application Monitor (SAM) > Polling fails due to null value for last Windows update returned during application monitoring (SAM)

Polling fails due to null value for last Windows update returned during application monitoring (SAM)

Updated: November 28, 2017


INTERNAL ONLY: This article is for internal use only and includes proprietary information. Do not make it public.

When the Agent polling method is used for a Windows node in SAM, agents communicate information collected by SolarWinds plug-ins to the Orion server. If the Windows Update Monitoring application template is assigned to the node, polling fails if a null value is returned for the System.DateTime value.

Note: This issue does not occur with WMI polling, agentless monitoring, or in SAM 6.5 RC1.


  • SAM 6.4


This issue occurs if Windows updates are not installed on a monitored node or if the Microsoft Update Service is not running. If the $colHistory variable is null, an exception occurs in the PowerShell script because a null value cannot be converted into a System.DateTime value. See the screenshot below and this Microsoft article for details.

SW Engineering used the following script to retrieve Windows update history:

  $objSession = New-Object -com "Microsoft.Update.Session"
  $objSearcher= $objSession.CreateUpdateSearcher()
  $colHistory = $objSearcher.QueryHistory(0, 1)



Direct the customer to start the Microsoft Update Service if it is not already running, and then install available updates.

The PowerShell script will be updated to resolve this issue in a future SAM release, tracked via SAM-6334.


Last modified



Internal Use Only