Why do I get unfortunately settings has stopped on my Gs6

[salwc2k]

Just got the marshmallow upgrade tonite on my Samsung GS6 but now everytime I go into settings and tap on "Themes" I get that error message (unfortunately settings has stopped). Was fine on lollipop. Is there a quick fix? Tried rebooting.

 

[lucianus_luciferus]

try clearing cache. if not you might need a factory reset