If you cloned a VM and want both VMs to work independently (each with its own license), you cannot simply clone. You must reset the fingerprint.
They will manually run a database query on Tenable’s backend to disassociate the activation code from the stale Challenge Code. This takes 24–48 hours for Standard support, 2–4 hours for Premium.
Accidentally attempting to use the same license key on a secondary test environment or backup scanner. Step 1: Reset the License via the Tenable Community Portal nessus offline activation license already in use
Once the license is freed on the portal side, you need to ensure your offline Nessus machine is generating a clean, accurate Challenge Code. Do not reuse an old challenge code text file. On Linux (Red Hat, CentOS, Ubuntu, etc.)
Write down this output. If this Challenge Code differs from the one you used during the first successful activation, you have found the mismatch. If you cloned a VM and want both
Transfer these files to your offline machine and register the license using: nessuscli fetch --register-offline Primary Contact Product Owner
This publication explains why Nessus can report an “offline activation license already in use” (or similar) error, how the offline activation process works, how to diagnose the root cause, and step‑by‑step remediation and prevention measures for administrators. It is written for security engineers and system administrators using Nessus in environments with limited or no direct Internet access. This takes 24–48 hours for Standard support, 2–4
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.
Now, return to your offline Nessus machine to apply the fresh license and load the vulnerability signatures. 1. Register the License File
Paste your newly generated into the first field. Input your reset Activation Code into the second field. Click Submit . The webpage will provide two vital components:
By following these steps, you can bypass the "License in Use" hurdle and maintain your security posture in even the most restricted environments.