any cache I should try deleting so that depth buffer appears again?

[drhouse]

I just experienced a frustrating problem. I ran Aliens - Dark Descent (Unreal 4 game), played around with 'Display Depth Buffers' settings and got whites/grays/blacks depths and 3D to work on my Vive headset (using VorpX Desktop Viewer for SBS) successfully.
But, after closing the game and restarting with the same Depth3D settings, the depth buffer only ever shows as black on the screen. I unsuccessfully tried: changing settings, solely using Depth3D without any VR or VorpX running, deleting/reinstalling Reshade and Depth3D filters for the game.
I'm wondering if maybe there's any type of cache I should try deleting, to reset things enough, so that the depth buffers may appear again? Or any other advice.