Mac Studio (M2) cannot detect display at start up until unplug and replug USB-C

Mac Studio - Technical Specifications - Apple

(Currently links to technical specifications for M2 Max / M2 Ultra models)

Four Thunderbolt 4 ports with support for:

• Thunderbolt 4 (up to 40Gb/s) 
• DisplayPort
• USB 4 (up to 40Gb/s)
• USB 3.1 Gen 2 (up to 10Gb/s)

On front (M2 Max):

• Two USB-C ports (up to 10Gb/s)
• SDXC card slot (UHS-II)

On front (M2 Ultra):

• Two Thunderbolt 4 ports (up to 40Gb/s)
• SDXC card slot (UHS-II)

So … only use the front-panel ports for connecting displays iff you have the M2 Ultra version. The back-panel ports are always "safe" no matter what variant of the Studio you have.

is yours the Max version system or the Ultra version system?

if the Max system, are results any different if you connect to the Back ThunderBolt ports?

what cables, adapters and docks are you using to make the connection to your displays?

are you cables certified and marked with the USB-C SuperSpeed+ symbol or better? and Limited to ONE meter or less in length?

Cables 'shipped in the box' are often found to be "lowest bidder' cables, and are just good enough to keep you from returning the device to the store.

alphaa wrote:

I have the M2 MAX

if the Max system, are results any different if you connect to the Back ThunderBolt ports?

YES. it will work if I unplug and replug USB-C back in. I have been doing that, and thats the only way to solve it.

That wasn't what he was getting at. The question was if things worked if you plugged the displays into the back USB-C ports, and left them plugged in.

On the versions of the Mac Studio with M1 Max and M2 Max chips, the front-panel USB-C ports are just for USB data transfers. Apple does not list them as supporting either DisplayPort or Thunderbolt. If you had a M2 Max Studio, and a display "sort-of" worked when plugged into the front-panel ports, that would be a case where the Mac would actually be exceeding promised specifications (though not in a useful way!). A first troubleshooting step would be to use the rear-panel USB-C ports, where DisplayPort and Thunderbolt are supported.

If you're already using the rear-panel ports, and you have to unplug and replug cables, then there's some issue other than the one he was getting at.

The Mac Studio with M2 max Processor has genuine ThunderBolt ports on the BACK. The FRONT ports are USB-C, limited to 10 G bits/sec by design. this can be a little different from expectations.

Your 4K full-color display requires a stream of data 17.28 G bits/sec for 10 bits/pixel color (30 bit-color) at full resolution and 60 Hz refresh. That is almost twice as much data as the front USB-C ports can provide.

So if it connects at all, it looks like something has to give. I would expect either 10-bit color drops back to 8-bit color (24-bit color), the fresh rate drops, or the resolution drops.

once connected, check:

 menu > about this Mac > (system report) > Graphics & Displays ... for this kind of report:

...

All Macs uses a system that reminds me of “Plug and play” to determine what display is connected, and what its capabilities are.

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

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

I'm having a similar problem, on my M1 Studio, with a USB-C to DisplayPort adapter, connected to one of the back-panel Thunderbolt ports. It was working 100% fine on the previous version of macOS, but ever since the Sonoma upgrade, it's stopped coming back from sleep reliably. I'm guessing that this is a bug in Sonoma's display plug-and-play, and it would be really nice if Apple still had a public bug tracker that people could submit bugs against because it's getting really irritating to have to unplug and replug my display ever so often.

Cables 'shipped in the box' are often 'lowest bidder' cables. That have can be just good enough to keep you from returning the device to the store.

If the cable shipped in the box does not have those markings, it is NOT a certified high quality cable.

HDMI is not using the same cable.

D2_Freed1-

you have camped on the ned of another User's problem, and when you post your specs, readers will be come too confused and unable to provide the help you need.

PLEASE start a fresh discussion, and remember to specify your display(s) specs and the interface cables in use.

Has anyone solved the problem of monitors not waking up? I have an m2Max and it's driving me crazy. Today I bought thunderbolt 4 cables from Apple and nothing changed. I have two HP Z27 monitors connected

Krzysztof_PL--

to get the attention you deserve, PLEASE start a NEW discussion.

This discussion is already way too crowded with different problems posted by different users with different hardware, different versions of MacOS, and different displays. If you did not immediately find your solution by reading through the existing postings, you do not have "exactly the same problem" and need to explain from the beginning.

That will allow readers to think hard about your exact situation and address the exact circumstances you are facing.