I know this is a reoccurring issue and I've gone through every forum, every topic and every blog post I could find. Two days ago my MacBook Pro 13 stopped detecting external monitors.
I'm using a Unitek HDMI to USB-C dongle which I know works fine. I've tested 3 different monitors, that have different resolutions and refresh rates, they all work fine.
I've got another 2019 MacBook Pro 13" that works fine with every single monitor; using the same cable/dongle combo.
What I've tried:
- plugged the dongle with and without charger also being plugged in,
- plugged the dongle when Mac was sleeping/off
- plugged in a USB-C -> USB-A dongle and connected a mouse to it - both ports work fine,
- restarted my Mac after I've plugged the USB-C cable in,
- reset NVRAM and SMC,
- reinstalled OS (with and without backup)
- tried clicking "Detect Displays" in Displays settings,
- closed the lid, plugged the cable in, opened the lid,
- installed DisplayLink drivers, uninstalled them.
When I connect the dongle, it's visible as BillBoard Device in the System Information -> USB (both Macs have that). I've also been watching and comparing Console logs when I connect/disconnect the monitor and here are some things that I've noticed:
- The Mac that works fine has some [Hot_Plug] events visible when I plug in the monitor,
- FB0 both have DisplayPort driver version 1.1, FB1 on working Mac has a version 1.2 (this information doesn't show up on non-working Mac)
The screen doesn't flicker when I connect any external display, there's no Arrangements tab visible. AirPlay works fine.
Both Macs are 2019 13" Pro with the same stuff inside - they both use Intel Iris 645 Graphics.