After running windeployqt on a binary, the program will fail to start claiming that the windows platform plugin can not be found or loaded.

To fix this, I can:

• Replace the deployed (and patched) Qt5Core.dll with the original version found in my Qt install dir. In this case the platform plugin is loaded from my Qt install dir :-/
• In my build directory, create a "plugins" directory and move the "platforms" directory inside it.

I could not reproduce in Qt 5.6.0/MSVC2015