MacBook M3 Pro + Dell UD22 – Only One Monitor Detected via USB-C + HDMI

jjatczak · 08-06-2025, 07:02 AM

Hi,

I have a MacBook M3 Pro and recently purchased the Dell Universal Dock UD22. Unfortunately, I'm unable to use two monitors at the same time when connecting them via USB-C and HDMI.

Here’s what happens: when I connect two monitors—one via USB-C and one via HDMI—they both display the exact same image, and macOS only detects one external display. However, if I connect them individually, everything works fine.

I've also tested this both with and without the DisplayLink software installed, and the behavior is exactly the same.

My question is:
Is this expected behavior? Is it not possible to use USB-C and HDMI outputs simultaneously for extended displays on the UD22 when using a MacBook, and should I be using DisplayPort instead?

Thanks in advance for your help!

08-06-2025, 07:02 AM	#1
jjatczak Junior Member Join Date: Aug 2025 Posts: 1	MacBook M3 Pro + Dell UD22 – Only One Monitor Detected via USB-C + HDMI Hi, I have a MacBook M3 Pro and recently purchased the Dell Universal Dock UD22. Unfortunately, I'm unable to use two monitors at the same time when connecting them via USB-C and HDMI. Here’s what happens: when I connect two monitors—one via USB-C and one via HDMI—they both display the exact same image, and macOS only detects one external display. However, if I connect them individually, everything works fine. I've also tested this both with and without the DisplayLink software installed, and the behavior is exactly the same. My question is: Is this expected behavior? Is it not possible to use USB-C and HDMI outputs simultaneously for extended displays on the UD22 when using a MacBook, and should I be using DisplayPort instead? Thanks in advance for your help!