Sequence of connecting USB-C monitor to Mac?

I have a MacBook Pro M1. I often connect to an external monitor via a USB-C to USB-C cable (the monitor has a USB-C port). But infuriatingly the monitor often says "no cable connected".

Is there a sequence to connecting to an external monitor?

Has the Mac got to be turned off and the monitor turned off, then I turn the Mac on, then the monitor after I've logged in? Or should I simply be able to connect the monitor to the Mac at any time, regardless of whether the Mac is off, asleep or awake? And should it not matter if the monitor is on or off when I connect it?

I've tried so many combinations and there doesn't seem to be any logic to how I get the two to connect. It's very hit and miss.

I'm using a USB-C data cable (that came with an external hard drive). It doesn't power my Mac, but it does allow me to use the monitor and the monitors USB ports as a hub.

MacBook Pro 16″, macOS 12.2

Posted on Mar 18, 2022 2:32 AM

Top-ranking reply

Grant Bennet-Alder

Level 10

140,741 points

Posted on Mar 19, 2022 7:38 AM

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

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Sequence of connecting USB-C monitor to Mac?

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