When you click Register in the Arnold License Manager, it runs the Autodesk tool AdskLicensingInstHelper. All Autodesk products use this tool to register themselves with Autodesk licensing.

Check the License Manager log

If you get Failed to register Arnold product, check the Arnold License Manager log.

On macOS:

1. Open the Arnold License Manager.
2. In the menu bar, click Arnold License Manager > About Arnold License Manager.
3. In the About dialog box, click Show Log.
4. Click Copy to copy the log, and send it to Autodesk licensing support.

On Windows:

1. In the Arnold License Manager, click Help > About.
2. Click Copy to copy the log.

If you want to try and troubleshoot the problem yourself, find the line that runs the AdskLicensingInstHelper register command. It will look something like this:

2021-11-08 11:13:10 DEBUG | [clmv2] run: "/Library/Application Support/Autodesk/AdskLicensing/Current/helper/AdskLicensingInstHelper" register --prod_key C0PL1 --prod_ver 2020.0.0.F --config_file /Applications/Autodesk/Arnold/mtoa/2022/license/pit/ArnoldConfig.pit --lic_method USER --eula_locale en_US

Under that line, there will be some log messages describing why the command failed.

Reinstall the licensing

In some cases, a complete uninstall and then re-install of “single-user licensing” can fix the problem.

In a Terminal, run these commands:

   cd ~/Autodesk/LicensingInstaller
   sudo ./uninstall.sh

sudo will ask you to type your password. Press ENTER after you finish typing.

Then start the Arnold License Manager and switch to Single-user licensing. The license manager will ask if you want to install single-user licensing.