Mac Studio M1 Max 2nd Monitor not working again!

Sorry only questions at this point.

1) What make and model are your displays...?

2) In detail, how is each display connected to the Mac Studio...?

3) in detail, what is the cable length and spec's of the cable going to that display..?

4) Does physically disconnecting and then reconnecting that display, force it to start working again...?

I don't know why but I had the exact thing happen on my 2019 Intel MBP. I doubt if they are related but maybe. I turned off the automatic graphics switching in settings then it worked. I then turned it back on and it stayed on.

lifeworksimaging wrote:

1. Main working monitor is a Mac Monitor. Secondary is a BenQ

What model number is the BenQ display..?

2. USB-C for both

Try staggering the display connections on the back of the Mac Studio.

One display to port 1 or 2 ports and one display to port 3 or 4.

3. 3 foot cable (honestly no idea what other details I could give you about the cord)

Not all USB-C cables are created equal. Many that are supplied by display manufactures work fine for PCs, but not Mac's. If you're using the BenQ supplied cable, try replacing it with an Apple Pro TB/USB-C cable.

4. No.

Sometimes that works and sometimes it doesn't.

I have tried switching from Extended to Mirrored and then back to extended. Doesn't matter.

If the cable is not up to the task, then the only way to fix it. Is to upgrade to a Pro cable or use a different type of connection like USB-C to DisplayPort or HDMI to HDMI, if the BenQ supports those connections.

Connect a display to Mac Studio - Apple Support

<< But it's worked for the last year and half with no issues. The only thing that has changed is the operating system. I also have tried disconnecting everything. Moving it over to my Mac Mini and setting up a second display with that and it works perfectly fine with no issues so it's definitely not a cable issue. >>

Iif the connection were marginal, especially due to cables that are too long or not quite up to the required specs, those would be expected symptoms, (i.e., stops working for no discernible reason.)

There have not been reports of inherent defects in these last few MacOS updates that could explain your issues.

Exactly what make &model display in each case?

That's what marginal means. It's right on the edge of working great. Sometimes it does, sometimes it doesn't.

But when some unknown item changes, like moving to a different Mac, or when things warm up, or when the processor is slightly different, or the relative humidity changes, it goes from working to not working, or goes back and forth between working and not working for no discernible reason.

So when you have a list of usual suspects that is known to help other Readers, you take a look at them and see if you can SHORTEN that list by removing troublemakers. and many times, everything perks up and works great after that.

I agree with you. If the cable worked fine for a year and a half and the only thing that changed was the update, then logically it seems to be software related. I would change to other ports/cables just to try variables, but to me it would point to the OS update. However, I have had cables go bad, especially modern chipped cables, so it would be reasonable to try all avenues.

Do you have any utilities that might mess with the display preferences such as gfsCardStatus?

You might consider resetting the display preferences then reboot.

rm -f ~/Library/Preferences/com.apple.windowserver.plist

the cables required for running high end displays at high resolutions and High Dynamic Range are switching at very nearly the limits of the ability of this type of digital logic.

For USB-C cables or USB-C-based cable/adapters the length limit for guaranteed reliable connections is ONE meter.

Using longer cables than that can cause marginal operation, and sometimes it won't work because recent versions of MacOS drop the connection if it makes an error.

Because the standards vary with different versions of HDMI, HDMI is a world of hurt unto itself, but for best results use certified ULTRA cables and try to keep cable lengths fairly short as well.

To let Apple know, send Feedback.

Feedback - Mac Studio - Apple

Feedback - macOS - Apple

if you post the EXACT make & model of your displays, I can look up the specs and interfaces, and may be able to provide additional advice.