Happens with me as well after updating to 1903.
At first, the icon changed to gray, and I had to go to Advanced tab on the Color Management in Windows, and uncheck the “Use Windows Display Calibration” box that turned itself checked after the Windows 1903 update.
Then, it was running okay, but during the day the DisplayCal stop working and the Windows takes control over it again, even if that box is unchecked, leaving me with this same Orange Icon.
The only turn around I’ve found was to Restart windows. But the issue occurs again at some point.
Probably there’s something on this new 1903 update that is overlapping DisplayCal configuration.
Will be following this thread in hope that someone find the fix.
I just did a DDU uninstall of the display driver an re-installed the last stable (non-hotfix) version and DispCAL is now behaving itself again. For now.
I checked the colour management options and the “Use Windows Display Calibration” is greyed out. Also, I’ve set the default profile to the same one DispCAL loads, so if DispCAL ever fails the correct profile should remain.