The Specify a default color machine setting should be configured correctly. This policy setting controls the default color for window frames when the user does not specify a color. If you enable this policy setting and specify a default color, this color will be used in glass window frames, if the user has not specified a color. If you disable or do not configure this policy setting, the default internal color will be used, if the user has not specified a color. Fix: (1) GPO: Computer Configuration\Administrative Templates\Windows Components\Desktop Window Manager\Window Frame Coloring\Specify a default color (2) KEY: HKLM\SOFTWARE\Policies\Microsoft\Windows\DWM\DefaultColorizationColorState