Rolling back a virtual machine to a state before Nessus was fully configured, or cloning a Nessus VM, clones the hardware UUID but breaks the cryptographic trust link with the license.
This error typically occurs in several common scenarios:
/opt/nessus/sbin/nessus-fetch --challenge
/opt/nessus/sbin/nessuscli fetch --challenge nessus offline activation license already in use
Confirm the action to change the status back to "Available." Step 2: Generate a New Challenge Code
Click the link. This makes the code available for a new installation without changing the code itself. 2. Generate a new challenge code
Nessus licenses come with a set validity period and a reset policy. The free Essentials license, for example, usually expires after one year. If the license is already bound to a system that is no longer available, or if you have tried to reset it too many times within a short period, the automated system may lock you out for a while. Rolling back a virtual machine to a state
This error triggers because Tenable associates your specific product license key with a unique hardware fingerprint (Challenge Code). If you attempt to apply the same license key to a new installation, a migrated server, or even a rebuilt virtual machine without clearing the old instance, Tenable’s activation server blocks the request to prevent unauthorized concurrent use.
nessuscli fetch --register-offline /path/to/nessus.license Troubleshooting Tips
You must release the license from the old hardware signature before activating it on the new one. Navigate to the and log in. Click on My Products from the main dashboard. If the license is already bound to a
Because offline licenses are manually tied to a unique hardware fingerprint, any change in your system configuration or a previous failed installation can block a new activation attempt.
Confirm the action. Your activation code status should instantly revert to or "Available." Step 2: Clear the Stale License on the Nessus Host
Workarounds and safe practices when contact is delayed or impossible