Microsoft and Intel discovered that on some computers with Intel display drivers users might have issues adjusting their display’s brightness because of a driver compatibility issue after applying the Windows 10 May 2019 Update. Microsoft has added a compatibility hold on devices with certain incompatible Intel Display Audio drivers from being offered the latest Windows 10 release until the issue is resolved. Microsoft advises all users to “not attempt to manually update using the Update now button or the Media Creation Tool”” until this issue has been resolved. Windows 10 version 1903 cannot be installed on computers with AMD Ryzen or AMD Threadripper processors.”
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-v1903-upgrade-blocked-due-to-some-intel-drivers/