I am working on building a plugin for AutoCAD. I have created a CUI file in AutoCAD 2025. However, when I try to load the same CUI file into AutoCAD 2021, I encounter the following error:
Customization File I/O Error:
"The customization file you are attempting to open is invalid. Select a different customization file and try again."
I have attached a screenshot of the error for reference.
I also tried using the "CUI window transfer feature", but I encountered the same issue.
Is there a way to resolve this problem without recreating the CUI file from scratch in AutoCAD 2021?
