I have tried several cycles of uninstalling and reinstalling the DisplayLink manager and extensions to no avail. It had been working previously - but I was away for a couple of weeks and I think an auto update caused the issues - has happened in the past, but have always been able to recover.
When I look at the Display Settings from Mac Systems Setting, I see the internal display and both connected LG UltraFine 24" monitors. The one connected via USB-C/Thunderbolt cable seems to work fine. The one using the StarTech USB32DP4K adapter (USB-A to DisplayPort to USB-C to LG Monitor) seems to be semi-active. It connects and I can move the mouse across the boundary, but the screen remains black and the monitor listing in the system settings indicates full brightness, but the control is inactive (grayed out). I think in one of the installs, a popup indicated that the driver was blocked by macOS, but was unable to find any hint of that in the Security settings.
Has anyone seen anything similar?
Screen capture available
here.
Apple iMac M1 (2021)
Belkin Thunderbolt 3 Dock Pro
2 x LG UltraFine 24" Monitors
macOS Sonoma 14.5