Could not find or load the qt platforms plugin "windows"

ynirkin

Hi,
I know this is a repeating issue but none of the suggested solution I found managed to solve this problem.

I get the following error on release configuration only: "This application failed to start because it could not find or load the Qt platform plugin "windows"".

It does work on debug configuration.
I did set the QT_QPA_PLATFORM_PLUGIN_PATH environment variable to "Qt\5.7\msvc2015_64\plugins\platforms" directory and I also tried to create a platforms directory in my exe directory and copy the qwindows.dll there.

I use Visual Studio 2015 Community with CMake 3.5.2 and Qt5.7.
My CMake code:

cmake_minimum_required(VERSION 3.1.0)
project(qt5_test)

# Find dependencies
# ===================================================
# Find the QtWidgets library
find_package(Qt5Widgets)

# Add executable
# ===================================================
#include_directories(${Qt5Widgets_INCLUDE_DIRS})
#add_executable(qt5_test WIN32 main.cpp main_windows.cpp)
add_executable(qt5_test WIN32 main.cpp)

# Use the Widgets module from Qt 5.
target_link_libraries(qt5_test Qt5::Widgets)

My application code:

#include <qapplication.h>
#include <qpushbutton.h>

int main(int argc, char **argv)
{
    QApplication a(argc, argv);

    QPushButton hello("Hello world!", 0);
    hello.resize(100, 30);
    hello.show();
    return a.exec();
}

Please help.

Thanks in advance,
Yuval

VRonin

Did you try with the windows deployment tool? http://doc.qt.io/qt-5/windows-deployment.html#the-windows-deployment-tool

ynirkin

@VRonin I tried now and it does work! Thank you.
But is there a way to make this work without copying the dlls around?

VRonin

you can use QCoreApplication::addLibraryPath to decide the search locations for your plugins

raven-worx

@ynirkin said:

It does work on debug configuration.
I did set the QT_QPA_PLATFORM_PLUGIN_PATH environment variable to "Qt\5.7\msvc2015_64\plugins\platforms" directory and I also tried to create a platforms directory in my exe directory and copy the qwindows.dll there.

You shouldn't set it to the "platforms" folder, but to the (parent) "plugins" folder instead.