Shameful cross-post from the general forum.
I get hundred of thousands of errors, like shown below, when I run the game in play mode with Mock HMD. They’re fired so often that Unity stutters and flickers, up to the point that I had to remove the MockHMD.
I can’t pinpoint exactly why it is happening, would you know how to fix it?
I’m on Unity 2020.1.13f1 and URP.
Attempting to determine the size of an unknown feature type Id [-1].
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)
I’m also having the same issue
Could you figure out where it’s coming from?
Same issue, unfortunately. Did you manage to find a solution?
Same issue too 
@showstopper-1 nothing yet, I think it’s on Unity’s end to fix this one. 
please raise a bug on this. cheers!
having the same issue
@Matt_D_work I’ve created a repro project and submitted the bug!
In case it helps anyone, I found I’ll get this error when my HMD isn’t connected to my computer.
I’m on Unity 2020.2.4f1.
Having the same issue on Mac Unity 2020.2 when adding MockHMD
May have found a solution by going to Project Settings > Player > Active Input Handling - Both instead of New. Fixed for now.
Doesnt work for me. It’s weird…
Having the same issue on Mac Unity 2020.3 when adding MockHMD
Haven’t they repaired this error? Is there really no a solution…
I’m having the same problem…
Robshocks answer worked for me. Switching to both instead of new fixed it immediately after rebooting unity from the changes.
Using Unity 2020.3.4f1in bootcamp
edit: nvm, no errors after the first launch after reboot but reverted back to errors on the launches after that. Weird
I am also experiencing this, and cannot use the Mock HMD on 2020.3.0f1
I am also facing this error. tried both for input, still, the problem occurring with 2020.3.0f1.
Hey man, could you share the ticket so we can follow its status?
I have tried this (robshocks solution ) but no luck. I am using Unity 2020.3.7f1 (64-bit) and MockHMD. Any other solution worked