This documentation supports the 21.05 (12.2) version of BMC Discovery.

To view an earlier version of the product, select the version from the Product version menu.

Troubleshooting unscanned hosts that are not being deleted

BMC Discovery may discover certain hosts that are no longer being scanned. Such persistently unscanned hosts are deleted or aged out in the system. At times, these unscanned hosts are not deleted or aged out automatically. Use this section to either resolve the problem or create a BMC Support case.  

Issue symptoms

When BMC Discovery no longer scans certain hosts, then BMC Discovery usually deletes such hosts automatically. For more information about how the hosts are deleted automatically, see Host node. Occasionally, some of these hosts are not deleted and continue to exist in the system, causing unnecessary overhead.


This issue impacts all versions of BMC Discovery.


Perform the steps listed in either of the following methods to manually delete the hosts that are discovered but no longer being scanned.

Method 1

Perform the following steps to exclude the IP addresses of the hosts that you want to delete:

  1. From the BMC Discovery main menu, select Manage > Discovery.
    The Discovery page is displayed.
  2. Click Add New Exclude.
    The Add a New Exclude Range dialog box is displayed.
  3. In Type, select Permanent and in Range, enter either specific IP addresses or a range of IP addresses that you want to exclude.
  4. Click OK.
  5. Rescan the IP addresses multiple times.
    The associated hosts are aged out based on the model maintenance settings.

Method 2

In this method, you run a query that identifies the unwanted hosts so that you can manually delete them. Perform the following steps:

  1. From the BMC Discovery main menu, select Explore > Query.
  2. Copy the following query.
    This query enables you to list the hosts that are not scanned successfully. In this example, the date is set to 2021-1-1. 

    search Host where last_update_success < parseLocalTime('2021-1-1 00:00:00') show name, 
    #InferredElement:Inference:Associate:DiscoveryAccess.endpoint as 'Scanned via', 
    last_update_success as 'Last Update Success'
  3. Paste the query in the UI and change the date appropriate to your case.
  4. Click Run Query.
    The query displays the list of unscanned hosts.
  5. Click Select All at the top-left of the UI.
  6. From the Actions list, select Destroy.
    The selected hosts are deleted from the appliance.

   If your issue persists even after trying these methods, contact BMC Customer Support and provide the results of the procedures you undertook.

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