With the Windows 10 May 2019 Update many users are reporting problems with screen calibration: what’s happening
Apparently many Microsoft users have encountered a bug that can interfere with the color settings and calibration of some monitors following the installation of the Windows 10 May 2019 Update. The Redmond-based company recently tried to fix the issue by releasing an additional update but the intervention failed to correct the error.
As confirmed by Nvidia and Reddit forums, as well as high-end monitor manufacturer Eizo, the bug reproduces colors falsely and generates vertical color grading lines. At the moment, Eizo advises against using a PC with Microsoft Windows 10 May 2019 Update installed, especially if you need to use photo editing programs. Microsoft stated that the recent patch KB4501375 released for Windows 10 May 2019 Update fixed the color management issues, but the problem persists for certain GPUs, as pointed out on the Nvidia forum.
Windows 10 May 2019 Update: how to try to fix it
However, there seems to be an alternative procedure that could fix the problem using a feature that can be activated via the Control Panel. The trick has been suggested by Windows Latest and it consists in opening the Control Panel (use Cortana to find it inside the PC), double-click to access the Control Panel Library, double-click on Microsoft and double-click again on Windows. At this point you should locate the WindowsColorSystem item and, in the Calibration window on the right, associate a Trigger to it. After that, it is necessary to disable the entries “When logging in” and “When accessing the user session”. Now you can restart the PC for the changes to take effect. This operation should fix the bug and allow correct color display on your monitor.
Windows 10 May 2019 Update: problems with VPNs too?
As reported by DisplayCal, the Windows 10 May 2019 bug also affected dedicated third-party calibration apps would seem to interfere with some VPN connections as well. This is an issue that concerns the KB4501375 patch itself, but fortunately it’s an error that the average VPN user shouldn’t encounter.