I was able to return my mobile phone to normal using the solution above but found a different dialog than negative. You need to go to your settings and find Accessibility. This is the area where you can make changes to help those with vision, hearing, access, difficulties. On my particular phone, the I had to turn off "Color Inversion". Here is the pathway. Settings - Accessibility features - Accessibility - Visual - Colour inversion Your pathway may be a little different just try and find a similar path under Accessibility. Good Luck!