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Review: Nessus Offline Activation and the "License Already in Use" Error

  1. Log in to the Tenable Support Portal.
  2. Navigate to Products > Product Activations.
  3. Locate the Nessus scanner/agent in your list.
  4. Click the "Release License" or "Deactivate" button associated with that specific activation code.
    1. Open a support ticket with Tenable. Under Reason, select "License Reactivation / Fingerprint Reset".
    2. Provide your license key and the hostname of the offline scanner.
    3. Request a manual offline reset. Tenable will regenerate the license association, freeing the "already in use" slot.
    4. Once confirmed, repeat the offline activation process from scratch:

      Did this solution work for you? Let us know in the comments below.

      Q2: I deactivated old scanners, but offline activation still says "full." Why?

      Step 2: Confirm License Type

      1. Confirm license usage status

      Copy this new challenge output exactly.

      Nessus Essentials

      : Note that Nessus Essentials (the free version) does not support offline registration; this feature is reserved for Professional, Manager, or Managed scanner versions.

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