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.

To check which version PyQt5 was compiled with

import PyQt5
print PyQt5.qt_version

plugin cannot be loaded for module "QtQuick"

See above

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

See above

What is this providing as opposed to the PYPI found: https://pypi.python.org/pypi/PyQt5/5.5.1

I believe that particular version doesn't actually contain binaries; it is merely a placeholder made by the original author.

You could try installing it, and see what happens.

$ pip install PyQt5