If you change your machine's hardware or virtual MAC address, the challenge code will change, requiring a license reset even if you are using the same "system".
With your reset activation code and your new challenge code, you can now generate the required license file. Go to the Tenable Offline Activation page.
If you've verified that your license key is correct and not in use elsewhere, but still encounter the error, it's time to contact Tenable Support. Provide them with:
You must release the license from its previous hardware attachment. Log in to the Tenable Community Portal. Navigate to or Licenses . Locate your specific Nessus Activation Code. Click Manage Product or the Reset button next to the code. nessus offline activation license already in use
If you know you are decommissioning a scanner, run nessuscli fetch --get-activation-code to confirm your details, and gracefully unregister it if it temporarily gains internet access, or proactively reset it in the portal before shutting the machine down.
Find the specific for your OS (Linux, Windows, or macOS). Troubleshoot plugin update errors. Explain how to automate this for multiple offline scanners. Let me know which operating system you are running! Share public link
This is a comprehensive review and technical breakdown of the "License Already In Use" error during offline activation for Tenable Nessus. This issue is notorious because it creates a paradox: you have a valid license code in your hand (or email), but the software rejects it because it believes it is currently running on a ghost machine somewhere. If you change your machine's hardware or virtual
If the error persists after a reset, check for hidden "zombie" instances. Ensure no other technicians are using the same code for a different lab environment. If you are using Nessus Essentials, remember that it is strictly limited to one activation; professional licenses offer more flexibility but still require a manual reset if the hardware footprint changes.
Take the nessus.license file back to your offline/air-gapped Nessus server via your secure data transfer method (e.g., an approved USB drive or internal SFTP). Register the file using the CLI: nessuscli fetch --register-offline nessus.license Use code with caution.
Select your product type (e.g., Nessus Professional or Expert). Step 2: Reset the Product Activation If you've verified that your license key is
Before you can generate a new offline license file, the existing "link" to your previous installation must be broken. Log in to the Tenable Community portal . Navigate to (usually in the upper right). Select your Nessus product type and click Manage Product .
If your organization frequently provisions and tears down offline scanning environments (such as infrastructure-as-code pipelines), resetting licenses manually through a browser is inefficient. You can leverage the Tenable.ot or Tenable Vulnerability Management APIs to programmatically release and regenerate activation codes before spinning up new offline instances. Avoiding Future License Locks