What exactly do you mean with "stop working"?
What is the version of your LR and OS?
Camera Raw 9.7
My Adobe CC is telling me those are the newest ones. I am also running the newest windows 10.
When I move the highlights and whites to value greater then 80, the rest of the sliders stop working. Weirdly enough, it only happens on some photos. Thank you for your time :-)
Attach a screen shot of one of the problem files. It would be even better to post a file with the problem on Dropbox or another site.