I didn’t have any problems with the registration about 40 minutes ago. I really like this program. I use my computer a lot and tend to get headaches after using it for many hours. I didn’t feel any tension but now when I switch from normal brightness to the program’s reduced brightness I feel the muscles around my eyes relaxing. So I think there was some tension around my eye muscles that I was not aware of when using full brightness. 3400K/100% seems to work well for me.