Hello. Hope someone can help. I just recently updated my daughters computer to Mavericks. She has a Late 2009 iMac with 12gig of memory (also recently added from 4 ). Everything has been fine for the first week or so and now she is getting inverted color on certian screens only. Password screen (see photo) and Updating software screens ). Once you login there is a very brief flash like the screen is going to be inverted but it turns out fine. I do not see anything in Accessibility that would make this happen. Everything is unchecked. She does have a 3 year old that hits numerous keys at the same time. I figure she has done something but I sure can not figure it out.