MacBook Air M2 stopped detecting an external monitor

[MacYost]

Hi all, weird problem here. My MacBook Air stopped detecting an external monitor which used to work fine until about a week ago. Both MBA and Monitor seem fine, but they don't like each other anymore...

I'm using an external 24" monitor on my MacBook Air M2 8/512 running 15.4. The monitor has a HDMI connector, and I'm using the Apple USB A / USB C / HDMI adapter to connect it to a USB C port on the MBA. This has worked fine since I bought the MBA, but it stopped working some week ago. I cannot think of a reason, it was not after an OS upgrade ore something like that.

Both monitor and MBA seem fine:

• I checked the monitor on a MacBook Pro M1 Pro, both with the adapter to USB C and directly to the MBP's internal HDMI port. In both instances the monitor is detected and works fine.
• I tried connecting another, 27" monitor, to the MBA and it was detected and worked fine (using the same adapter as before).

The weird thing is, that the monitor "sees" that the MBA is connected. When I plug it in, it comes out of sleep mode and seems to get a signal. When I plug it out, it says "no signal detected". But my MBA doens't see the monitor, also not when I try to "force" Detect External Monitor in the System Settings. The problem is apparent on both USB C ports.

Any ideas to get this working again are highly appreciated. Thanks!

 

[BrianBaughn]

Troubleshooting step: Try in a new, test user account.

 

[MacYost]

@BrianBaughn, sorry for the late response... I tried it in a new user account. Everything stays the same as described in my first post. Anything else I can try, before I'm doing a clean install on this MacBook? I would rather avoid reinstalling everything...

 

[BrianBaughn]

You can do a re-install that's not a "clean install" and keep settings as they are. Not sure either is going to help.

Component combinations can be finicky. It may be that other cables or adapters will work. You could try a USB-C hub with an HDMI port.