Fixing M1 Mac External Display Issues (Flickering Screen, White Noise, Black Screen, etc)
Some M1 MacBook Pro, M1 MacBook Air, and M1 Mac Mini users have discovered display issues when using an external display connected to their M1 Mac. Typically the M1 Mac external display issues are either a flickering display, a display that won’t wake from sleep and where the screen stays black, or a white noise display visible after the Mac has woken from sleep, or after the display has slept or turned off and is attempted to be used by the Mac again.
If you’re experiencing external display issues with an M1 Mac, read on to learn about possible fixes and workarounds to the display flickering, white noise showing, black screens that won’t wake, or other similar issues.
This issue seems to exist regardless of which dongles, display connectors and adapters, or display cables are used, and whether or not it’s a compatibility issue between the M1 Mac series and certain external displays, a bug with macOS that has yet to be resolved, or some other problem, is not yet clear. Some users have reported success with using a USB-C to HDMI or USB-C to DisplayPort cable with the M1 Mac, instead of a dongle or adapter, but that does not resolve the problem for everyone.
How to Fix External Display Issues with M1 Mac
There are a few fixes and workarounds to external display issues with the M1 Macs, here’s what you can try if you are experiencing these problems:
Disconnect and reconnect display cable
If the external screen is flickering or displaying white noise, you can try to disconnect and reconnect the cable while the Mac is powered on.
This will cause the M1 Mac to refresh its own display, as well as the external display, which typically resolves the problem immediately.
Variation: Disconnect/Reconnect display cable from dongle (not from Mac USB-C port)
For my own M1 MacBook Pro, simply disconnecting and reconnecting the USB-C dongle adapter from the Mac does not resolve the display flickering or white noise issue. Instead, I’ve found disconnecting and reconnecting the HDMI cable from the USB-C dongle adapter itself works.
Rebooting the Mac
Rebooting the Mac also appears to often fix the display flickering problem, but this is annoying and should not be necessary for most Mac users. Instead, try the approaches discussed above with disconnecting and reconnecting the cable.
If the display won’t wake at all, forced restarting the M1 Mac seems to temporarily fix the issue (until it is put to sleep again, anyway).
Workaround: Disable Display Sleep
Preventing the display from going to sleep also prevents the display flickering problem. You can do this a few different ways:
Completely Disable External Display Sleeping on Mac
- Open System Preferences from the Apple menu
- Choose “Battery” (M1 MacBook Pro, M1 MacBook Air), or “Energy Saver” (M1 Mac Mini, iMac)
- M1 Mac laptops choose “Power Adapter”, and then drag the slider for “Turn Display Off After…” to “Never”
Temporarily Prevent Display Sleep with a Hot Corner
Setting up a Hot Corner and choosing “Prevent Sleep” as the Hot Corner configuration, then remembering to throw the mouse cursor into that corner, will prevent sleep when used.
Install MacOS Software Updates when available
Though this issue persists with modern macOS versions (including macOS Big Sur 11.4, macOS Big Sur 11.5, and macOS Monterey for some users), installing the latest available macOS system software updates may resolve the problem eventually, particularly if it’s a bug that Apple has fixed.
You can update macOS system software through Apple menu > System Preferences > Software Update.
A previous issue with the M1 Mac Mini having issues with displays not waking from sleep was apparently fixed with macOS Big Sur 11.3, but some users still experience the problem with later macOS versions, or variations of the issue (flickering screens, white noise, monitor stuck on black, etc), and with other M1 Mac models.
Try a Different Cable or Connection Method
Sometimes a particular display may have issues with one cable, but not another. Or sometimes a particular connection method may have problems, but another does not.
For example, some users may have problems with a cheap USB-C to HDMI dongle, but find that another higher quality USB-C to HDMI adapter may work fine, or if HDMI is not working then a USB-C to DisplayPort cable may work.
I was able to completely fix my flickering external display and noisy external display on a M1 MacBook Pro by switching from HDMI with a dongle to a Warky USB-C to DisplayPort cable that’s compatible with my external display. Anecdotal, but it’s something to consider, especially if the temporary fixes like unplugging and plugging the cable back in are getting to be annoying.
Miscellaneous Solutions to External Monitor Issues with M1 Macs
Mixed reports have also mentioned the following can be helpful:
- Using a different USB-C port, cable, or adapter
- Using a different connection method (ie: DisplayPort rather than HDMI on the display)
- Setting the external monitor as the primary display on the Mac
“My M1 Mac works with external display fine, but the refresh rate is too low”
Some M1 Mac users also have discovered the refresh rate available used by an external display is 30hz, rather than the smoother 60hz, 120hz, 144hz, or higher options.
Certain HDMI cables, adapters, and dongles may be the reason the display is not showing 60hz or greater available as an option.
However, if you know the display cables are working with another device at 60hz, you can typically manually change the refresh rate on a Mac display with these instructions. You can also check refresh rate in use on the display as discussed here. A 30hz refresh rate is usually fairly obvious and not subtle, as the mouse cursor is typically choppy, as are dragging windows around on screen, and playing games or watching movies is choppy too.
Do you have display issues with external screens and your M1 Mac? What are the problems you are having, and how did you resolve them? Did you find another solution not mentioned here? Share with us your experiences, tips, and suggestions in the comments.