FAQ

QQmlApplicationEngine failed to load component

This may be due to a conflicting version of Qt already existing on your system.

The Qt runtime always looks at c:\Qt for binaries before resorting to it's associated qt.conf so if you've got a version of Qt installed that doesn't align itself with the version used to compile PyQt5 then you might get this error.

plugin cannot be loaded for module "QtQuick"

See above

PyQt5/qml/QtQuick.2/qtquick2plugin.dll: The specified procedure could not be found.

See above