cinema 4d a “substance failed to load” is keeping me from opening my project

I’m not sure why I can’t even open my project to fix the issue. but I get a pop up window that says “substance failed to load” when i click ok or hit the close button it wont go away. It wont let me exit this warning so I can never even open my project. I can't even quit out of cinema 4d its stuck on this error message.