Macbook Horizontal Lines Across Screen . I sometimes get these horizontal lines all over the computer, it looks like it's been smashed on the ground. First they have changed logic board and top It does not affect the performance but horizontal lines on the screen which appear once in a while usually scrolling pictures is quite annoying when. Flickering pink and blue horizontal lines when windows are ... (Tom McLaughlin) It was acting completely normal, then it created horizontal lines across the screen. Two crossed lines that form an 'X'. For last two months two horizontal lines are appearing across the screen width almost in the middle of the screen. I want to know why these lines are appearing when the notebook has been handled with care. Red Vertical Lines, Image Distortion, Screen Blurring, Freeze, Shift. MacBook Problem - Lines in Screen | Doovi Vertical and ...