The message “GetKeyIndex” appears on some render nodes when rendering with Backburner from 3ds Max. The render may then fail on those nodes.

In the Backburner.log files, the message appears as:

ERR Task error: 3dsmax adapter error : Autodesk  22.1 reported error: MAXScript ExecuteMAXScriptScript Exception: -- No ""getKeyIndex"" function for undefined


  • 3ds Max
  • Backburner


Includes, but is not limited to:

  • Plug-in version mismatch between submitting Manager machine and one or more render nodes.
  • MaxtoA (3ds Max to Arnold) render version mismatch between one or more machines.
  • Corrupted Backburner settings on one or more render nodes.


To address this issue, do the following:

1.Go to the Windows Control Panel > Programs and Features and verify the version numbers for all copies of 3ds Max — they must be identical across all machines, both Manager and Server nodes.

  • If the versions differ, log into your Autodesk Account, download the latest update for the version of 3ds Max being used, and install it on all machines.

2. The Max-to-Arnold plugin for the Arnold renderer must also be identical on all render machines, even if the Arnold renderer is not being used, and the 3ds Max copies are version-identical across each PC.

  • Go to the Arnold Downloads webpage, then download and install the latest version of the Arnold renderer for every version of 3ds Max being used in network rendering (both Manager and Server nodes).

3. Reset Backburner on the faulty render node by following these instructions: Reset Backburner user settings to default.

4. If none of the above steps works, try resetting the 3ds Max user preferences back to the default settings as well.

See also

Source: Autodesk

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