Activation is required each time I start 3ds Max / I am getting crashes / material editor slots are black!

This article applies in case of problem such as:

  • Corona asks for activation each time 3ds Max is restarted
  • Any rendering crashes with "fatal error" message or similar
  • All material editor sample slots appear black when Corona is selected as the active renderer
  • Various other issues appear - such as Corona VFB displayed incorrectly, interactive rendering not working

Possible solutions

Solution A - Reset your activation files:

  1. Note: this first step applies only If you were asked by Corona staff to provide additional files/ logs. Otherwise you can skip it and go to point 2 below.

    Go to C:\Users\_username_\AppData\Local\CoronaRenderer and send us the content of this folder.

  2. Make sure that you are able to see the hidden files and folders in Windows. To enable this, go to "Folder Options" in Windows settings, go to "View" tab, and make sure that "Show hidden files, folders, and drives" option is enabled.
    Then, go to C:\Users\_username_\AppData\Local\CoronaRenderer and make sure that none of the .txt files in there has the "hidden" file attribute enabled in its properties (Right click on a file > Properties > Attributes > Uncheck "hidden").

    In case the above point did not help:

  3. Go to C:\Users\_username_\AppData\Local\CoronaRenderer and remove all files inside this folder.
    while this is perfectly safe to do, it will require re-activation of Corona upon the next 3ds Max launch.

Solution B - Disable the NVIDIA AI Denoiser

  1. Set Corona as your active renderer in 3ds Max.
  2. Go to Render Setup > Scene > Denoising and set Mode to None.
  3. Go to Render Setup > Performance > Interactive rendering and disable the "Fast preview denoise during render" checkbox.

If you are still experiencing some issues after trying solutions A and B, please contact us