To help troubleshoot this issue, it would be helpful to have more information about your specific use case and material setup.
1. Can you tell me more about what you are trying to achieve with this script?
2. How are you using the CoronaColorCorrect map in your material setup?
3. Are you using Corona 9 or a more recent version which is Corona 9 HF 1?
4. What version of 3ds Max are you using?
I apologize for the delay in reply.
1. I can't tell anything special about the script. This is a simple script that should just clear the "copiedMap" property, but instead I get the error I wrote above. If you just click on the slot with the map and select <NONE> in the Material/Map Browser, then it works and the slot is cleared and "copiedMap" property becomes "undefined", but if you try to do it through maxscript, you get an error. As far as I understand in maxscripts (and I understand enough), then assigning the value "undefined" to a property intended to refer to a texture map should not cause an error.
2. There is nothing supernatural in the map settings. This is a regular CoronaLegacy material and a regular CoronaColorCorrect map (Map #1), with another CoronaColorCorrect map (Map #2) from which the color correction settings are taken (see screenshot below).
3. Corona 9 (hotfix 1)
4. 3ds Max 2023.2.2 Update
