# /opt/nessus/sbin/nessuscli fetch --register-offline nessus.license
It turned out that the previous owner of the license had not properly deactivated it before transferring it to me. This oversight led to the license being flagged as "already in use." I was surprised that Tenable's system did not have a more robust process in place to prevent such issues.
On the where Nessus is installed, you must generate a unique "challenge code" that identifies that specific system. Update License Offline (Tenable Nessus 10.12)
License already in use – Full license
Changing the network interface card (NIC), upgrading the CPU, or altering the MAC address of a virtual machine, which changes the hardware challenge string.
Since a Nessus license can only be assigned to one host at a time, you must release it from its previous "online" or "offline" assignment. E-SPIN Group Tenable Community/Support Portal My Products Products and Activation Codes on the left menu. your Nessus Professional or Expert activation code. Click Reset Manage Product > Reset Product Activation next to the code. the reset. The status should now show as available. 2. Complete Offline Activation
Click on the button (or similar offline activation prompt). Select the Offline tab. Copy the new Challenge Code . Step 3: Get the New License File (Offline) nessus offline activation license already in use full
Reinstalling Nessus on the same machine after an OS wipe without resetting the license.
Navigate to the or "Manage Nessus Activation Codes" section. Locate the activation code currently marked as "in use".
Once the code is reset, follow these steps to activate your air-gapped system: # /opt/nessus/sbin/nessuscli fetch --register-offline nessus
: On a machine with internet access, go to the Nessus Offline Registration page . Enter your Activation Code and the Challenge Code you just generated.
Remember these key takeaways:
Resolving this error requires a methodical approach. Do not repeatedly attempt activation—this can lock the license for 24 hours. Update License Offline (Tenable Nessus 10