20:54:07.599: Initializing D3D11...
20:54:07.599: Available Video Adapters:
20:54:07.613: Adapter 0: NVIDIA GeForce 940MX
20:54:07.613: Dedicated VRAM: 2107703296
20:54:07.613: Shared VRAM: 2086811648
20:54:07.613: output 0: pos={0, 0}, size={1920, 1080}, attached=true
20:54:07.613: Adapter 1: Intel(R) HD Graphics 620
20:54:07.613: Dedicated VRAM: 134217728
20:54:07.613: Shared VRAM: 2086811648
20:54:07.622: Loading up D3D11 on adapter NVIDIA GeForce 940MX (0)
20:54:07.950: D3D11 loaded successfully, feature level used: b000
20:54:07.950: D3D11 GPU priority setup failed (not admin?)
You can't run display capture on a laptop with both integrated (Intel) and discrete (Nvidia) GPUs while OBS is running on the discrete GPU. Switch to the Intel.
Laptop? Black screen when capturing? Read here first.
If you've installed Windows update 1909, you need to make this change in Windows display settings and not the Nvidia control panel.
https://github.com/obsproject/obs-studio/wiki/Laptop-GPU-Selection-Windows-10