I vaguely remember that people have reported something similar before. But I don't know whether there is a fix for this:

I was working in Carrara when it froze and I had to kill it using process termination. Now whenever I have a figure into which I inject a morph, the morph comes in locked (I cannot change the value, if it came in set at value 1.0, it stays as 1.0, if it came in at 0.0, it won't apply. As I slide the morph value slider, it changes and I see the morph being applied, but as soon as I release the hold on the slider, it goes back to the original value).

Is there a fix for this? Is it something in the registry? Did my figure files get messed up somehow?

I don't think I've seen this behavior persist over reopening of files before. This time I've tried reopening the base file, starting a new file and introducing the figure to the new file, closing Carrara, opening it again with new file and then introducing the figure. I even reinstalled Carrara, and it is still happening!