Use Link — Nessus License Already In

Reinstalling the OS or the Nessus software on the same machine may cause it to be recognized as a "new" system due to a changed MAC address or hardware ID.

After resetting, use nessuscli fetch --register to re-register the scanner. 3. Transitioning Between Systems nessus license already in use

: Open the terminal and run: /opt/nessus/sbin/nessuscli fetch --deactivate 3. Re-register Your Current Instance Reinstalling the OS or the Nessus software on

Navigate to the section in the upper right corner. Transitioning Between Systems : Open the terminal and

The error (often appearing as "Code in Use") typically occurs when you attempt to activate a Tenable Nessus instance with an activation code that is currently registered to another system. Because Tenable Nessus licenses are generally limited to one active scanner at a time , you must release the code from its previous assignment before it can be reused on a new installation. Common Causes of License Lockout

: Go to Settings > License and enter your Activation Code.

Attempting to run two active scanners on a single Professional license. Step-by-Step Solutions 1. Reset via the Tenable Community Portal (Recommended)