This error effectively locks you out of applying a legitimate license, leaving your vulnerability scanner in an unlicensed or "disabled" state. This article provides a deep dive into why this error occurs, how to diagnose it, and step-by-step solutions to resolve it permanently.
: Select the specific Nessus Professional activation code that is triggering the "already in use" error.
Note: If you have already tried to activate the new machine and got the error, you must generate a new challenge code, as the old one is now invalid.
Tenable’s offline activation portal caches license usage for up to 1 hour. Wait 60 minutes, regenerate a new challenge file, and retry. nessus offline activation license already in use full
# Windows C:\Program Files\Tenable\Nessus\nessuscli.exe fetch --register-offline C:\path\to\nessus.license # Linux /opt/nessus/sbin/nessuscli fetch --register-offline /path/to/nessus.license Use code with caution. Alternative: Deactivating via nessuscli
Reinstalling Nessus without deactivating or purging the license database will preserve the same broken state. You must delete the license cache as shown in Solution 5.
Run the appropriate command on your offline machine to generate a fresh, updated hardware identifier. Open Command Prompt as an Administrator and run: This error effectively locks you out of applying
Restart Nessus. In some cases, the license will become valid again.
This tells Tenable to release the activation slot immediately.
The administrator injects this Reclamation Token back into the offline Nessus scanner via the UI or command line. Nessus validates the cryptographic signature of the token against its local trusted keys. Note: If you have already tried to activate
The error "Nessus offline activation license already in use" occurs because Tenable Nessus activation codes are restricted to . If you are moving your license to a new offline machine or re-installing it, you must first release the license from the previous installation via the Tenable Support Portal. Step 1: Reset the Activation Code
When attempting to activate Nessus in an offline (air-gapped) environment, users frequently encounter the License already in use error. This occurs because the license was not properly deactivated on a previous instance (e.g., a VM that was destroyed or a scanner that crashed), and the Tenable cloud portal still registers it as active.