Captivate 12 won't save after updating theme

I am using Captivate 12. I tried to update the background color in my theme (I already have a project started) and when I went to save changes, the app hung and I had to force quit out of Captivate 12. This happened three times and I was never able to make global changes to the template.

Has anyone had this experience, and is there a solution?

Thanks,

Natalie