Troubleshooting the "Nessus Offline Activation License Already in Use" error can be frustrating, especially when you are working in a secure, air-gapped environment. This specific error typically triggers when the Nessus activation code is already linked to a specific Challenge Code or Host ID in the Tenable system.
Note: Only the Primary Contact or assigned Product Owner has permission to perform this reset.
You must manually reset the activation code through the Tenable Support Portal to make it available for a new challenge code. Log in to the Tenable Community/Support Portal.
Linux/macOS: nessuscli fetch --register-offline /path/to/nessus.license Troubleshooting Tips
When you retire a server, immediately manually deactivate the license via the Tenable portal before turning the server off.
(or the "X" / "Reset" button) next to the code. This unlinks the code from any current hardware ID. E-SPIN Group 2. Generate the Offline License File Once the code is reset, you can proceed with the standard offline registration process Get Challenge Code
The "License already in use" error during Nessus offline activation is almost never a true indication of piracy. It is typically a mismatch between the hardware signature Tenable has on file and the current state of your server. By manually fetching the challenge code and resetting the license on Tenable’s portal, you can resolve the issue in under ten minutes.
