Activation is required each time I start 3ds Max and all material editor slots are black!


This behavior was fixed in Corona Renderer 1.5 hotfix 2 and should never appear again. Please contact us if you encounter it.


This article applies in case of a problem where:

  • Corona asks for activation each time 3ds Max is restarted
  • Any rendering crashes with "fatal error" message
  • 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


Possible solutions:

  1. This is the first, most important step:
    Go to C:\Users\_username_\AppData\Local\CoronaRenderer and send us the content of this folder.

  2. Go to C:\Users\_username_\AppData\Local\CoronaRenderer and make sure that none of the .txt files in there has "hidden" file attribute in its properties (Right click on a file > Properties > Attributes > Uncheck "hidden").
    Note: Make sure that you are able to see the hidden files and folders. 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.

    OR - mainly in case the 1st solution does not work:

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