Nessus Offline Activation License Already In Use Full

A: You cannot deactivate an offline scanner remotely. Instead, use the Tenable portal to deactivate it manually by selecting the entry and clicking "Deactivate" – this work even if the scanner is offline forever.

Resolving this error requires a methodical approach. Do not repeatedly attempt activation—this can lock the license for 24 hours.

Step 1: Identify the Exact Error Context Run the following on the scanner:

cat /opt/nessus/var/nessus/logs/nessusd.log | grep -i "license"

Look for lines containing "already in use" or "fingerprint mismatch." nessus offline activation license already in use full

Step 2: Check for Orphaned License Files Navigate to /opt/nessus/var/nessus/ and check for license or nessus.license files. If present, back them up and delete them:

sudo mv /opt/nessus/var/nessus/nessus.license /tmp/nessus.license.bak

Step 3: Generate a Clean Challenge File Stop the Nessus service:

sudo systemctl stop nessusd

Remove the old challenge cache:

sudo rm -f /opt/nessus/var/nessus/nessus-challenge.txt

Generate a fresh challenge:

sudo /opt/nessus/sbin/nessuscli fetch --challenge

Copy this new challenge output exactly.

Step 4: Deactivate the Lost/Stale License (Critical Step) This is where most guides stop, but it is essential. You must contact Tenable Support or use the Tenable Customer Portal (if you have online access on a separate machine) to deactivate the license tied to the old system ID. A: You cannot deactivate an offline scanner remotely

If you cannot access the portal (fully offline), you must call Tenable Support with your license activation code and the output of nessuscli fetch --challenge from the new scanner. They can manually release the lock.

Step 5: Perform the Offline Activation Again On an internet-connected machine, go to https://license.tenable.com/offline_activation. Upload the new challenge file. Download the resulting nessus.license file. Transfer it to the offline scanner (USB drive). Install it:

sudo /opt/nessus/sbin/nessuscli fetch --register-offline /path/to/nessus.license

Before attempting any fix, perform the following diagnostic checks. Look for lines containing "already in use" or