If your Mac display doesn’t look right
If the image on your Mac display doesn’t look right, try one or more of these suggestions.
If the display is black or dim: Try adjusting your display’s brightness.
If images are too large or too small: Try adjusting your display’s resolution.
If the colors don’t look right: Try using the display profile designed for your display. For example, if you’re using a Thunderbolt display, choose Apple menu > System Settings, then click Displays in the sidebar. (You may need to scroll down.) Click the pop-up menu next to “Color profile” on the right, then choose Thunderbolt Display. If that doesn’t work, try calibrating the display.
If your display is blurry: Make sure your Mac has detected that display. Choose Apple menu > System Settings, then click Displays.
To see the Detect Displays button, press the Option key. Then click the button to detect the display.
If the display is flickering: Make sure your Mac and display are connected to one another with good quality cables and adapters. You may also be experiencing interference from a nearby power line, a fluorescent light, a radio, a microwave oven, another computer, or another electrical device. Try relocating nearby electrical devices, or moving your Mac and display.
If you see bright or dark spots on a flat-panel or Mac laptop screen: Your display may have pixel anomalies. If you suspect your Apple display contains a high number of anomalies, contact Apple or an Apple Authorized Service Provider for service. Repairs performed by untrained individuals or using non-genuine Apple parts may affect the safety and functionality of the device.
If none of these solutions work: If you have an Apple display and can’t correct the problem, contact Apple or an Apple Authorized Service Provider for service. Repairs performed by untrained individuals or using non-genuine Apple parts may affect the safety and functionality of the device.