So your new Macbook’s clamshell mode is not working and you’re looking for a solution. The problem seems to be more common on the latest M1 Macbooks.
Luckily for you, I came across a few possible fixes that might work. Clamshell mode allows you to use your Macbook with the lid closed, connected to an external monitor, mouse, and keyboard.
Why is MacBook Clamshell Mode Not Working?
If your Macbook’s clamshell mode is not working enable the “Prevent Computer from Sleeping when Display is Off” option. Another solution could be that your Macbook is on, but the external monitor doesn’t support the saved resolution, showing a black screen.
The solution would be to remote access your Macbook from another device, and change the display settings remotely, through TeamViewer or AnyDesk, while still in clamshell mode. The issue seems to be you can only change monitor settings while in clamshell mode.
Make sure to double-check Apple’s official guide on connecting external monitors.
I’ll expand on these solutions below.
How to Stop Your Macbook from Sleeping in Clamshell Mode:
The steps vary slightly depending on your version of the Mac OS. The steps below are for Big Sur 11.0.
- Click the Apple logo on the top corner
- Select System Preferences
- Click on Battery
- Select Power Adapter
- Use the slider to choose how long until the display turns off.
- Enable “Prevent computer from sleeping automatically when the display is off”
In most cases, enabling these power saving options will keep your Macbook awake when connected to an external monitor in clamshell mode.
Recommended MacBook: M1 MacBook Pro
M1 MacBook External Monitor Black Screen in Clamshell Mode:
This problem is quite common and it usually occurs because display settings are saved in clamshell mode, even settings that are not supported. For example, the external monitor was working with your Mac before but you changed a setting and now it shows a black screen.
The solution is to change the display settings while still in the clamshell mode to something that your monitor supports. Of course, that’s not an easy task when you can’t see the screen.
A workaround is to use remote access software like TeamViewer. If you don’t have a separate laptop or PC, TeamViewer has a mobile app that you can use to remotely access your Mac from your phone.
You can install these programs when your Mac is not in clamshell mode (so you can use the built-in display to see what you’re doing) and then close the lid and connect it to the external monitor again. From there, you can use a separate device to remotely access your Mac while it’s in clamshell mode to change the display settings.
You might have to try a few different options, such as the resolution or refresh rate until the monitor detects a signal. Unless there’s a problem with the USB-C display adapter hub or your monitor, that solution should fix the problem.
Wondering if you can use multiple monitors with a Macbook?
Other Possible Fixes:
1 – Make sure your Macbook is plugged in
To save battery, most Macbooks will automatically go to sleep when they’re not plugged in. It won’t damage your Macbook to have it plugged in all the time.
Some power delivery docks can be unreliable. I recommend plugging the Macbook directly into a wall outlet using the official power adapter. If you see the charging icon on the battery, the clamshell mode should work.
2 – Double check your USB-C hub
Let’s face it, some cheap USB-C hubs are garbage. I suggest disconnecting the hub and testing it with a different device with the same monitor. It’s an easy way to help troubleshoot the issue.
To narrow it down, test the hub on a different monitor, if it doesn’t work, it’s probably time to buy a new hub. Here’s a good Macbook USB-C dock.
3 – Disconnect your monitor’s power cable for 5 – 20 seconds
If your monitor was working before, there’s likely a configuration error in the software. One possible solution would be to simply unplug the monitor from all power sources and leave it for 5 – 20 seconds.
Leaving the monitor unplugged will force the monitor’s settings to reset. Next, connect all the cables, and hopefully, the monitor should work with your Mac once again.
Recommended Vertical Stand:
Once your Macbook’s clamshell mode is working once again, I recommend buying a vertical stand. The Twelve South BookArc for Macs is a great modern vertical stand with cable managed features included.
A vertical stand will save desk space while allowing you to be productive with an external display. It also keeps the Mac elevated. You can even place it behind your monitor to save even more desk space.
It’s very frustrating when a Macbook’s clamshell mode does not work as intended. The solutions above should fix the problem.
Have you had issues with clamshell mode? What did you do to fix it? Leave a comment below.