Issues connecting Dell D6000 docking station to 3 external displays using MBP M2 2023 running macOS Sonoma

I found a faulty hdmi cable and now it is working as it did for four years in this configuration - so Merry Christmas it is :)

The dell 6000 is a Windows-centric USB-C Dock from an era when displays were tiny, and there was plenty of bandwidth for anything and everything you wanted to connect on one cable.

Today, one 4K display consumes as much as 18 G bits/sec of a 20 G bits/sec USB-C cable. The era of many displays on one USB cabled Docking device has gone forever, at least on Macs.

In order to support up to TWO displays on one cable, you need FAR more bandwidth that a single USB-C cable can generally provide. On a Mac: the computer port, the connecting cable, and the first device (Dock or Display) must ALL be genuine ThunderBolt devices.

Three on one cable of any description is not supported.

I have a similar problem, but I know it's not related to resolution because I replaced 3 monitors with lower resolution.

For four years on two Macs - previous one was AMD64, current one is M1 - I ran three monitors on the Dell D6000 with 3 Dell UltraSharp U2412M 24-Inch monitors at 1920 x 1200 (these are not hires) - with 3 display port cables and the HDMI port converted to RGB by a short dongle.

I replaced the Dell monitors with VA2456-MHD 24 Inch (1920 x 1080) - also not hires, but upgraded to IPS and 100hz refresh. Should be no bandwidth issues.

All three ports will work for a while - but when I powerdown and undock the mac, when I come back and reattach the HDMI won't activate.

When I fiddle with all sorts of things it eventually starts working, but I can't figure out why.

Everything is the same. Same firmware on the dock.

I've tried:

• moving the HDMI port between different monitors.
• completely replaced the HDMI cable with a new one
• Reinstalled the display port adapters.
• Even tried the HDMI to 25 pin dongle.

Works for while until the dock state changes substantially - it was never this temperamental before.

for the M2 Pro processor:

Simultaneously supports full native resolution on the built-in display at 1 billion colors and:

Up to two external displays with up to 6K resolution at 60Hz over Thunderbolt, -OR- one external display with up to 6K resolution at 60Hz over Thunderbolt and one external display with up to 4K resolution at 144Hz over HDMI

One external display supported at 8K resolution at 60Hz or one external display at 4K resolution at 240Hz over HDMI

for the M2 Max processor:

Simultaneously supports full native resolution on the built-in display at 1 billion colors and:

Up to four external displays: Up to three external displays with 6K resolution at 60Hz over Thunderbolt

-AND- one external display with up to 4K resolution at 144Hz over HDMI

Up to three external displays: Up to two external displays with 6K resolution at 60Hz over Thunderbolt and one external display with up to 8K resolution at 60Hz or one external display with 4K resolution at 240Hz over HDMI

Thunderbolt 4 digital video output

Support for native DisplayPort output over USB‑C

HDMI digital video output

Support for one display with up to 8K resolution at 60Hz or 4K resolution at 240Hz

>> so you have the ports, just plug them in.

The Mac is now checking for errors in transmission, and is unwilling to support a display that generates an error.

The supported setup for TWO displays on one cable requires Thunderbolt cable, computer-port and Dock. Three displays on one cable is not supported.

Users here don't know any reliable "cheats". "Not supported" means if you get it working, "Merry Christmas!" If you can't get it working, no help is available.

which model? {13-in, 15-in, 14-in, 16-in?}