If you need to install the Autodesk Network License Manager:
- Open the Arnold License Manager and click File > Install License Server
Or download the installer and run it
- Connect to the license server
I have an Arnold 2020 license, but I want to use Maya 2018
You can use an Arnold 2020 license in any version of Maya, 3ds Max, Houdini, CINEMA 4D, Katana, or Softimage, as long as there is an Arnold 6 version of the plugin available.
For example, you can use an Arnold 2020 license with Maya 2020, Maya 2019, and Maya 2018.