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Home > Success Center > Network Performance Monitor (NPM) > Remove disappeared APs

Remove disappeared APs

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Created by Con Finucane, last modified by samuel.rourke on Jul 20, 2017

Views: 1,848 Votes: 5 Revisions: 7


Note: The following article applies to NPM 11.5.3 and earlier. If you wish to achieve this functionality in NPM 12 or newer please see the following article: Remove Disappeared APs in NPM 12 or later


By default Wireless Access Points that disappear are removed from the database. This means that they cannot be alerted on by Orion Alerts.

We can modify the configuration of Orion to change this behavior so that Access Points which disappear will be left in the Orion in an Unknown State.


Note: If the following configuration change is implemented APs will no longer be deleted from the database.


NPM versions 11.5.x, 11.0.x and 10.7​


Warning: SolarWinds strongly recommends that you create a backup of the following file:

C:\Program Files (x86)\SolarWinds\Orion\Wireless\SolarWinds.Wireless.Collector.dll.config

Modify the CONFIG file using a text editor:

  1. Find the following key:
    <add key="RemoveDisappearedAPs" value="True" />
  2. Change the key to the following:
    <add key="RemoveDisappearedAPs" value="False" />
  3. Save the changes.
  4. Restart Orion Services.



The functionality works in the following way:


<add key="RemoveDisappearedAPs" value="True" />

  •  When the AP disappears from the controller's SNMP it's removed from NPM.
  •  An AP which disappears cannot be alerted on as it gets removed from the Database.

<add key="RemoveDisappearedAPs" value="False" />

  • When an AP disappears from the WLC's SNMP the Access Point will go into an Unknown State in NPM.
  • If the AP appears on another WLC it will appear as a new Access Point.
  • When the AP comes back to the old WLC again, the once disappeared AP is marked as UP again.
  •  An alert can be triggered for when a AP goes into an Unknown State (Disappeared) and reset the alert when the AP reports in an Up status.


If the APs are not removed after following these steps, it could be due to the device recording the details of the AP rather than dropping the data.

See the below article for more details:


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