Since the update to Lightroom 6.6, I've been seeing the 'black image bug' in develop module again very frequently.
Basically 1/3 of my photos appear black when viewing them in the develop module.
If I select 'View' 'Before', the original is displayed correctly, when switching to 'After' it's black again. Even in split-view the 'Before' side is image, the 'After' side is black.
If I play around with some settings and then select 'Auto' the image is displayed correctly again.
If I deactivate GPU acceleration, then all images are displayed correctly, however I would like to use GPU acceleration.
Any thoughts how to fix the issue?
Is there some kind of logging that I could activate that would help you to fix the bug?
Lightroom version: 6.6 [ 1078672 ]
Operating system: Mac OS 10
Version: 10.11 
Application architecture: x64
Logical processor count: 8
Processor speed: 2.5 GHz
Built-in memory: 16,384.0 MB
Graphics Processor Info:
AMD Radeon R9 M370X OpenGL Engine
Check OpenGL support: Passed
Vendor: ATI Technologies Inc.
Version: 4.1 ATI-1.42.6
Renderer: AMD Radeon R9 M370X OpenGL Engine
The issue will probably be fixed with 6.6.1 or 6.7 - when - only Adobe knows.
Until then your solution is to turn off GPU acceleration or roll back to 6.5.1. Do you use a 4k or more display? If not, I assume you don't see any gain in performance anyway, do you?
Simply replace 6.1.1 by 6.5.1.
Stefan, did you update your Mac OS version recently on your computer?
I have not updated to the very latest version (10.11.5), but am still running 10.11.4.