Before updating our production machines I always test a new macOS release (even point releases) on a dedicated test MacBook. Software-wise this notebook is a close match to productions ones.
After the upgrade to Big Sur 11.0.1 finished, I was greeted with this (don’t read the image’s title if you don’t like spoilers):
Spoiler: macOS Big Sur fails to properly use table-based v4 ICC profiles…
It was suspicious even during the upgrade that something wrong is going on: there was no difference between checked and unchecked states of the presented check boxes.
Now, I have installed Big Sur betas and even the final release on the very same MacBook on an external disk countless times, with no such issue.
It turned out pretty quickly that the cause is the custom ICC display profile. I do profile each display on production machines, as we’re doing color-critical work on them. And I also think that all monitors are color-important, so they have to be properly calibrated and profiled.
Interestingly, some older profiles exhibited this issue, others showed the regular Catalina “blue cursor” issue, while a few were OK. After an afternoon’s worth of debugging and work, here’s what I found.
- With matrix-based profiles (v2 or v4) Big Sur fails to color-manage the cursor (mouse pointer, etc), which looks odd blue (D50 and 5300K are our standard color temperatures, so a 7000-8000K cursor stands out like a sore thumb). This is the exact same bug that plagued Catalina.
- Big Sur is unable to handle v4 LUT-based profiles properly. The dock, the background, and most window manager stuff is totally washed out, as you can see on the screen grab. Interestingly, content in apps (like Safari) is OK, so I guess that this is just a Dock/window manager bug.
- v2 LUT-based profiles work as expected! And this is the solution for now: use v2 profiles… In i1Profiler LUT-based profiles are called table-based.
Speaking of i1Profiler, I’m still using an oldish i1Pro v1 spectrophotometer, and the latest version of i1Profiler that supports this instrument is 3.1.1. I have found no issues with this version for display profiling on Big Sur (just don’t install the HASP drivers).
And the important takeaway: re-profile your monitor to create a v2 profile before upgrading, otherwise you won’t see your checkbox choices during the upgrade!
More to come on solving other issues to make Big Sur livable…
