Your external monitor is connected but stays black

Why it happens

A black monitor that's switched on usually means the picture isn't getting through, not that the screen is broken. The cable may be loose, the monitor may be on the wrong input, or the Mac may be sending a signal the monitor can't show, such as a refresh rate it doesn't support.

How to fix it

1. Check the monitor is on and set to the right input, such as HDMI 1 or DisplayPort. Use the buttons on the monitor to change it.

2. Unplug the cable at both ends and plug it back in firmly. If you use an adapter or dock, try plugging the monitor straight into the Mac, or use another port.

3. Open Displays and click the monitor at the top of the page. Set Use as to Mirror so it shows the same picture as your Mac's screen. If that works, you can switch back to extended display afterwards.

   Displays›Use as

4. On the same page, choose a lower Refresh rate, such as 60 Hertz. Many monitors stay black at a rate they can't handle.

   Displays›Refresh rate

5. Still black? Restart your Mac with the monitor plugged in.

   Apple menu›Restart…

Still not fixed?

1. If the monitor isn't listed in Displays at all, hold the Option key. The Night Shift… button at the bottom changes to Detect Displays. Click it.

   Displays›Detect Displays

2. Black after the Mac wakes from sleep? Press a key or move the mouse, then use Detect Displays. If it still doesn't come back, unplug and replug the cable.

3. Turn off High Dynamic Range for that monitor if it's on. Some monitors go black when HDR is switched on.

   Displays›High Dynamic Range

4. Check how many external displays your Mac supports. Some MacBook models drive only one, so a second monitor stays black. Your Mac's tech specs on Apple's website list the number. Some docks also need their maker's own software.

5. If the monitor stays black with another computer too, the monitor is at fault, so contact its maker or a repair shop. If every monitor and cable stays black on your Mac, its port may need repair, so contact Apple Support.