SOLVED External display does not work on the USB-C ports on the right side

[wxsabi]

I have a 2020 MacBook Pro 16"(2019 model) nice machine, kinda outdated now that Mx chips are out, etc,... Anyways, I've had no issues with it up till recently where my external 4K display does not work if I connect it to any of the two USB-C ports on the right side, whereas if I connect them on the other side, it all works fine. I can tell that the monitor detects the MBP and viceversa, because for 3-5 seconds the mac detects the KB and Mouse that are connected to the monitor. This proves that there is data transfer, at least for a few seconds between the devices and then it dies. Once I connect the monitor's USB-C cable on the left side, the external monitor shows the desktop and all the peripherals connected to it work with no issues.

Can anyone point me in the right direction to troubleshoot and check why this happens?

The USB-C ports on the right side work properly for flash drives and anything else I've connected to them, except for an external display.

Thanks,
wxsabi

 

[Cory Cooper]

Hello and welcome.

I would try this: Reset the SMC of your Mac

Also, have your tried a different cable, or the HDMI port?

C

 

[wxsabi]

Hello and welcome.

I would try this: Reset the SMC of your Mac

Also, have your tried a different cable, or the HDMI port?

C

that solved it. I reset SMC and PRAM and it now works like a charm. Dunno what caused it, though. This MBP does not have HDMI ports, only 4 USB-C.

Thanks Cory.