Make sure you have at least one microphone sound device (like Headset Microphone - Oculus Virtual Audio Device) enabled!

Did some extra digging as this topic mentions some variations that don't result in error logs for people:

https://forum.unity.com/threads/unable-to-start-oculus-xr-plugin.913883/

For me, going back some versions of the Oculus XR plugin managed to get it in a working state.

1.4.0 works
1.4.3 works
1.5.1 crash

We will be sticking on the 1.4.3 now so we can start using the LTS version. But there is an issue with the later Oculus XR plugins at least.

Still happens in 2020.3 LTS
Exact same crash.

My reproduction steps, 100% reproducable on my machine.
- Install XR management plugin 4.0.1
- Install Oculus XR plugin 1.8.1
- Press play in the SampleScene

Still happening.
Unity 2020.2.2f1
Oculus XR Plugin 1.7.0 package.
XR Plugin Management 3.2.17 package.

work fine.
Unity 2019.3.0f6

This is still happening for me with the latest version of unity and the oculus integration. Any new suggestions?

Have this issue as well on (19.4.8f1 20.1.2f1)seem that new XR manager have issue with GPUs(findout that if i plugin Oculus hdmi to primary GPU where is my monitor connected aswell its working, but if i connect Oculus to secondary GPU editor will crash) so if u have more GPUs try connect your VR hdmi to primary GPU. Also try to disable Intel integrated GPU in bios if u have one.

I'm still having this problem with 2019.4.x (1f1, 6f1, 7f1). Oculus desktop software is 19.0.0.364.531.

Unity "run" works fine initially. i import the XR Integration Toolkit (preview) 0.9.4. Go to "Project Settings..." and click the install XR button. checkmark "Oculus" on Desktop tab. Now if i press Run button it will crash (reliably).

This is on Windows 10 Enterprise PC (64 gb ram, intel i7-7700kCPU @4.20GHz, NVIDIA GeForce GTX 1080 Ti). ... (tho i also see Intel HD Graphics 630 listed under Display Adapters in Device Manager)

What's weird is i can go in the other room with a different PC (Windows 10 Pro) and everything seems to work. Same Unity and Oculus software versions. but the hardware is : 16 gb ram, i5-6600k CPU @3.5GHz, Nvidia GeForce GTX 970). ... (I ONLY see nvidia listed under display adapters.)

Have this issue as well, (Unity 2019.3.14f1) the VR works fine for a few hours of starting and stopping whilst developing, then either get a black screen for VR or Unity crashes. Not sure what is causing this but VR works fine on my system, albeit my system is somewhat old. It is as though memory leaks and fills up the system video memory, or thinks it has, because Oculus VR still works fine even if VR does not work with Unity (XR) - then I am not that aufait with all the technical interaction with VR and Unity - probably something I need to read up on.

Confirming this is still an issue on 2019.3.14f1

Also reported on Unity 2019.3.10 ... fixed for me when Oculus Desktop completed its self-upgrade to v16 (something seemed to be temporarily messed up while Quest was on 15, Desktop on 16 - which Oculus officially supports, but ... perhaps not so well :))