In Eureka, a new Discovery performance enhancement named Probe Results Cache was introduced. This feature caches the last probe results. After the first Discovery run, if probe results do not change in subsequent runs, the probe results payload is not sent from the MID Server to the ServiceNow instance and sensor processing is skipped. One of the out-of-box probes cached is the installed software probe. So, if no new software was installed or deleted for a device since the last Discovery run, the sensor does not run. This causes an issue when the Discovery and the Software Asset Management (SAM) plugin is installed.

SAM has a background job that deletes installed software if they have not been refreshed within the last 7 days. Because the sensor will not run if the results have not changed, entries in the SAM installed software table (cmdb_sam_sw_install) start getting deleted. When viewing software lists in the SAM plugin, the user will find that software entries are missing.

To resolve the problem, upgrade the instance to Eureka Patch 7 or later. If upgrading from an affected version, clear the cache in order to rediscover the deleted software. To accomplish this, follow the workaround instructions to disable the cache for all of the "* Installed Software" probes. After completing this step, re-enable the cache for the probes. There is no need to wait for Discovery to run first as disabling the cache removes the cached results immediately. The next time Discovery runs it repopulates the entries that were deleted.

If an upgrade is not possible at this time, please refer to the workaround below.

Steps to Reproduce

This issue occurs for customers where the following are all true:

  • The instance is running a Eureka version Patch 6 or lower
  • Discovery is installed
  • The Software Asset Management (SAM) plugin is installed


To confirm the version and active plugins for your instance, leverage the two links below:

Displays the affected plugins.  Check the Status column to determine if the plugins are active.


To confirm the version, go to https://<instance_name>.service-now.com/stats.do and look for the value for Build tag.



Disable the probe results cache for the installed software probes.

  1. Locate all the installed software probes:


  2. For each of the installed software probes, clear the Cache results option.


  3. Click Update. 

    This bypasses the probe results cache until the issue is fixed.
Reminder: Turn the probe results cache back on after the issue is resolved in the product.


Note: This counts as a customer update for these probes. All future changes are not automatically applied during upgrade. For more information, see the Manage Customizations section in Upgrades Best Practices..




Related Problem: PRB614375

Seen In

Eureka Patch 10
Eureka Patch 2
Eureka Patch 3 Hot Fix 1
Eureka Patch 4
Eureka Patch 4 Hot Fix 4
Eureka Patch 5 Hot Fix 1
Eureka Patch 6
Eureka Patch 7 Hot Fix 1
Eureka Patch 8

Fixed In


Associated Community Threads

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Article Information

Last Updated:2016-07-25 12:51:35