Reset Activation Code
You do not need to reset your activation code for the latest Nessus versions, and you are able to re-register the same license with your original activation code.
In Nessus Professional 7.x and earlier versions, if you uninstall and reinstall Nessus, you need to reset your activation code. Reset your activation code on the Tenable Community site, as described in the Tenable Community Guide.
Note: Reset codes have a 10-day waiting period before you can reset your code again.