External monitors can't be detected after upgrading to macOS 26.1

My new Mac Mini M4 Pro does not recognize the Thunderbolt connection to an ASUS PA32QCV 6k display.

The Mac Mini came with macOS 26.1. Update to 26.2 didn't fix it. Multiple Thunderbolt 4 cables from different vendors didn't work. Changing Thunderbolt connections didn't make a difference.

Thunderbolt connection to a Samsung 4K monitor (LS32D800) works fine using the same cables. The Mac Mini Thunderbolt ports all work with that monitor.

On the PA32QVC side, the Thunderbolt connection is reported as failed. HDMI connection directly to the Mac Mini works fine.

Since I haven't had the Thunderbolt connection work with that ASUS monitor, I'm unable to determine the source of the problem - Mac or ASUS monitor. Next step is to submit reports to Apple and ASUS.

Bugs can be reported to Apple here:

Feedback - macOS - Apple

I have the same problem. Everything worked fine until i updated to 26.1.

It was working fine on 26 and 26.0.1.

I have the Problem on both Macbook M1 Pro Max and Macbook Air M4.

My Setup:

• Two Dell G2724D connected via DisplayPort-to-usb-c to the Hub
• CallDigit Thunderbolt 4 Element Hub
• One Thunderbolt 4 cable from the Hub to the Mac.
• Note: i am aware of Bandwidth limits with TB4. Therefor one Monitors runs at 1440p@165Hz and the other one at 1440p@60Hz. This setup worked well as mentioned above on older OS versions before 26.1

The Problem:

When both Monitors are connected to the Hub and then i connect the hub (via TB 4) to my mac, the mac lags, then Monitors are black and not recognized and i get a notification from Mac:

Accessory Not Enabled
Unnamed Device
Use a Dsiplayport-capable cable and port to connect the accessory

When Only One Monitor is connected to the Hub, No Problems.

We need a solution for this!

LF523 wrote:

My new Mac Mini M4 Pro does not recognize the Thunderbolt connection to an ASUS PA32QCV 6k display.

Update to 26.2 didn't fix it. Multiple Thunderbolt 4 cables from different vendors didn't work. Changing Thunderbolt connections didn't make a difference.

Thunderbolt connection to a Samsung 4K monitor (LS32D800) works fine using the same cables. The Mac Mini Thunderbolt ports all work with that monitor.

Recommended high quality cables: labeled certified ULTRA HDMI or PREMIUM ≤ 1.0 m length

or USB-C Thunderbolt5 cables ≤ 0.5 m length cables rated for high speed data.