When GPU is off, Lr relies on the macOS Windows Color management facility to the color management transform (this is especially beneficial in multiple display setup). This is probably why you see the OS level apps all exhibits the same problem.
GPU on, Lr does its own Adobe color management (like Photoshop) for the main develop loupe display that avoid the macOS bug (because the platform offers no color management support for the GPU render path).
My main color profile causes the biggest problem as you see in the screen shots. Other profiles like the default uncalibrated monitor profile or AdobeRGB do cause crushing in shadows but the shift is more on par with the previous version of LR.
Simon, I went through the threads. The problem is similar and I can replicate this problem within OS level apps like Safari, image preview, etc.. All other color managed apps like Photoshop, DaVinci Resolve, Capture One, Firefox, etc do not suffer this problem.
The previous version of LR did have some slight variation in shadows but nothing to this extent. I've attached screen shots of GPU enabled and disabled with the current and previous version of Lightroom side by side for comparison.
I have the same problem as Tice. See attached photos.
Develop Module
Library Module
Lightroom Classic version: 7.0 [ 1140024 ] License: Creative Cloud Operating system: Mac OS 10 Version: 10.12 [6] Application architecture: x64 Logical processor count: 8 Processor speed: 3.5 GHz Built-in memory: 32,768.0 MB Real memory available to Lightroom: 32,768.0 MB Real memory used by Lightroom: 901.9 MB (2.7%) Virtual memory used by Lightroom: 2,085.3 MB Memory cache size: 7.6MB Maximum thread count used by Camera Raw: 5 Camera Raw SIMD optimization: SSE2,AVX,AVX2 Camera Raw virtual memory: 333MB / 16383MB (2%) Camera Raw real memory: 337MB / 32768MB (1%) Displays: 1) 2560x1440
I do not seem to be able to reproduce the problem, PC running Win 8.1.
Lightroom Classic version: 7.0 [ 1140024 ] License: Creative Cloud Operating system: Windows 8.1 Version: 6.3 Application architecture: x64 System architecture: x64 Logical processor count: 8 Processor speed: 3.4 GHz Built-in memory: 32644.1 MB Real memory available to Lightroom: 32644.1 MB Real memory used by Lightroom: 1781.9 MB (5.4%) Virtual memory used by Lightroom: 2281.5 MB GDI objects count: 777 USER objects count: 2392 Process handles count: 1234 Memory cache size: 346.0MB Maximum thread count used by Camera Raw: 5 Camera Raw SIMD optimization: SSE2,AVX,AVX2 Camera Raw virtual memory: 1351MB / 16322MB (8%) Camera Raw real memory: 1658MB / 32644MB (5%) System DPI setting: 96 DPI Desktop composition enabled: Yes Displays: 1) 2560x1440 Input types: Multitouch: No, Integrated touch: No, Integrated pen: No, External touch: No, External pen: No, Keyboard: No
And just in case anyone from Adobe wants it, here's my system info:
Lightroom Classic version: 7.0 [ 1140024 ] License: Creative Cloud Operating system: Mac OS 10 Version: 10.11 [6] Application architecture: x64 Logical processor count: 8 Processor speed: 2.6 GHz Built-in memory: 32,768.0 MB Real memory available to Lightroom: 32,768.0 MB Real memory used by Lightroom: 4,517.7 MB (13.7%) Virtual memory used by Lightroom: 5,585.7 MB Memory cache size: 7,196.3MB Maximum thread count used by Camera Raw: 5 Camera Raw SIMD optimization: SSE2 Camera Raw virtual memory: 1677MB / 16383MB (10%) Camera Raw real memory: 1715MB / 32768MB (5%) Displays: 1) 2560x1440