#11913 (Bug) Profile loader reloads profiles every few seconds under Windows 10 April update
I just updated to the Windows 10 April update (Windows 10 Pro 10.0.17134). Since updating, I am seeing DisplayCAL's profile loader update my monitor calibration roughly every fifteen seconds. (I just let it run for four minutes and it told me "calibration state was (re)applied 17 times today" when I clicked it.) I have been getting similar reapplication rates since I updated, and I see the little icon spin.
These appear to be reloads due to false positives in the change detection, as when I disable "preserve calibration state" or quit the profile loader, the monitor's calibration stays perfectly fine—unless I run an application that resets the profile. I don't believe I have any other applications that would be modifying the profile (unless Microsoft is doing something silly in the new version of Windows). The fact that my calibration persists when the profile loader is disabled seems to suggest that these are some form of false positives.
Unfortunately, this seems to be causing a significant issue and not just wasting a few CPU cycles: when the profile loader is active, my displayed image has been occasionally flashing to the identity ramp for a short time (a single display refresh, I suspect). This has happened at the same time I've seen the profile-reload animation. Disabling the profile loader seems to have stopped this behavior as well. I'm not intimately familiar with Windows display drivers, but my suspicion is that when the profile loader tells Windows to install the display profile, the ramps get momentarily reset to the default color ramp by either Windows or the Nvidia driver, and that this intermediate state is only ever drawn to screen if it happens to overlap the moment when a display refresh begins. This hypothesis fits the observation that the profile is gets updated several times per minute but I've only seen the identity-ramp refreshes a few times per hour. (This has been intermittent so I will update the ticket if I see anything that conflicts with this hypothesis.)
I was running DisplayCAL 3.5.2 initially, but I upgraded to 3.5.3 and am seeing this behavior. (I didn't check the reset rate on 3.5.2, so I'm not positive as to whether the behavior was identical before the update to 3.5.3.) I've attached my logs directory, though the logs don't seem to include the timing and reasons for profile installation. I'd be happy to collect more information if it would be helpful. I have tried rebooting, restarting Profile Loader, and reinstalling the profile.
I'll rig something up with AutoHotKey so I can manage without the profile loader for a few days, but I'd love to see this fixed. Thanks in advance!
dispcalGUI (application/zip | 2018-05-09 08:44:35)