Published 2021-10-05 by TechNet New England
An external display gives you more room to work. Here is how to connect and configure one with your Mac. ## Step 1: Identify Your Connection **MacBook Air/Pro (M1 and newer):** USB-C / Thunderbolt ports. Most external monitors connect via USB-C to USB-C, USB-C to HDMI, or USB-C to DisplayPort cable/adapter. **MacBook Air M1/M2:** Supports 1 external display natively. A second external display requires a DisplayLink adapter. **MacBook Pro M1 Pro/Max and newer:** Supports 2 or more external displays depending on the chip. **Mac Mini, Mac Studio, Mac Pro:** Check Apple's specifications for the number of supported displays. These typically have HDMI and Thunderbolt ports. **iMac:** Thunderbolt ports for external displays. ## Step 2: Connect Plug the cable from your Mac to the monitor. If you need an adapter, use an Apple-branded or reputable third-party adapter (CalDigit, Anker, Belkin). The monitor should be detected automatically. You will see your desktop extend to the new display. ## Step 3: Configure 1. Open **System Settings > Displays**. 2. You will see both displays listed. Click **Arrange** to position them relative to each other. 3. Drag the displays to match your physical setup. The white menu bar indicates the primary display. Drag it to whichever monitor you want as primary. ### Resolution Click each display to set its resolution. Choose **Default for display** for the native resolution, or select **Scaled** to adjust the effective resolution (making things larger or smaller on screen). ### Refresh Rate If your monitor supports high refresh rates (120Hz, 144Hz), select it from the **Refresh Rate** dropdown. This requires a compatible cable and port. ## Mirror vs. Extend By default, macOS extends your desktop to the new monitor. If you want both screens to show the same content (for presentations): 1. Go to **System Settings > Displays**. 2. Click the **Arrange** button. 3. Check **Mirror Displays**. Or press **Command + F1** as a keyboard shortcut to toggle mirroring. ## Troubleshooting **Monitor not detected:** Unplug and replug the cable. Try a different port. Try a different cable. Restart the Mac with the monitor connected. **Flickering or artifacts:** Usually a cable issue. Replace the cable with a higher quality one. Make sure it supports the resolution and refresh rate you are using. Avoid cable adapters chained together. **Only one external display working (MacBook Air):** MacBook Air M1 and M2 natively support only one external display. For a second display, you need a DisplayLink adapter (such as the Plugable USB-C DisplayLink adapter). **Resolution looks wrong:** Go to System Settings > Displays and select the correct resolution. If options are limited, the cable or adapter may not support the monitor's native resolution. **No sound from monitor:** Go to **System Settings > Sound > Output** and select the monitor as the audio output device. **Dock and menu bar on wrong display:** In System Settings > Displays > Arrange, drag the white menu bar to the display you want as primary.