Nessus — Offline Activation License Already In Use |link|

Once you have the reset activation code and the new challenge code: On a machine with internet access, go to the Nessus Offline Registration page Enter your Challenge Code Activation Code , then click Download the nessus.license

Understanding the root causes helps prevent the issue during future maintenance.

If you followed these steps and still receive the "Already in Use" error, it usually indicates a backend sync issue at Tenable. In this case, providing your Activation Code and the new Challenge Code to a Tenable Support ticket is the fastest path to resolution. nessus offline activation license already in use

With a reset license and a fresh challenge code, you can now complete the offline registration without triggering the error.

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. Once you have the reset activation code and

💡 : Always keep a backup of your nessuscli fetch --challenge output. If your hardware profile changes (like swapping a NIC), your challenge code changes, which will trigger a license mismatch. If you’re still stuck, I can help you:

If you cannot deactivate via the portal, back up your scan data, reset the Nessus installation, and contact Tenable Support with both the old and new challenge codes. With proper deactivation discipline, you will never see this error again. With a reset license and a fresh challenge

If you plan to decommission a server, always run nessuscli fix --reset or nessuscli fetch --unlink while it still has connectivity, or manually release the key in the Tenable portal immediately during the teardown phase.

Copy the custom URL provided on the screen to download the latest . Step 4: Apply the License and Plugins Offline

Enter your and the Challenge Code you just generated.