I have a bit of an odd issue with my 2020 MacBook Air (M1) and Dell U4021QW monitor.

When the Mac goes to sleep whilst connected to the monitor, the monitor doesn't go into standby. The screen is dark, as in nothing is being displayed, but the monitor is not sleeping, it's still still on just not having a signal.

My work Mac is an older intel MacBook Pro, when connected through the same thunderbolt port in the monitor (and cable) it doesn't have this issue, when the laptop goes to sleep, the Dell monitor goes into standby as expected. I get similar results on my PC workstation, which is connected to monitor via DP.

I checked the battery section on both Macs, and all seems similar.

Anybody have any clues how to proceed troubleshooting this?

1 Answer 1


Did you update to the latest firmware? The latest has a June 2022 release date, referencing a fix to the "Macbook M1 issue":


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