Statically linked app with Qt gives error: Failed to load platform plugin “windows”

Question

I have built Qt 5.0.1 statically in VS 2010 under Windows 7 x64. The configuration parameters were

configure -debug-and-release -opensource -confirm-license          


        

Answer 1

To check what DLL are needed to deploy your application on Windows, use dependency Walker (http://www.dependencywalker.com/).

According to the documentation page Qt for Windows - Deployment some DLL are required to deploy a Qt application on Windows platforms:

• qwindows.dll
• icudtXX.dll
• icuinXX.dll
• icuucXX.dll
• libGLESv2.dll
• libEGL.dll

Depending on the compiler you use to compile the application, some other libraries may be required:

• MSVC specific libraries:
  • msvcrXX.dll
  • msvcpXX.dll
• MinGW specific libraries
  • libgcc_s_dw2-1.DLL
  • libstdc++-6.dll

Note: in all these files, replace XX by the current version of the DLL on your system.

If you didn't build Qt statically (default), you will also need Qt5 DLL depending on Qt module you use in your application. Example:

• Qt5Core.dll
• Qt5Test.dll
• Qt5Network.dll
• etc.

All these DLL can be found in "bin" folder, under your Qt installation dir.

EDIT

Recently, Qt developers created a tool named windeployqt.exe which helps you to gather all required library to deploy an application:

Usage: windeployqt [options] [file]
Qt Deploy Tool 5.3.0

The simplest way to use windeployqt is to add the bin directory of your Qt
installation (e.g. ) to the PATH variable and then run:
  windeployqt 
If ICU, ANGLE, etc. are not in the bin directory, they need to be in the PATH
variable. If your application uses Qt Quick, run:
  windeployqt --qmldir  

Options:
  -?, -h, --help            Displays this help.
  -v, --version             Displays version information.
  --dir          Use directory instead of binary directory.
  --libdir            Copy libraries to path.
  --debug                   Assume debug binaries.
  --release                 Assume release binaries.
  --force                   Force updating files.
  --dry-run                 Simulation mode. Behave normally, but do not
                            copy/update any files.
  --no-plugins              Skip plugin deployment.
  --no-libraries            Skip library deployment.
  --qmldir       Scan for QML-imports starting from directory.
  --no-quick-import         Skip deployment of Qt Quick imports.
  --no-translations         Skip deployment of translations.
  --no-system-d3d-compiler  Skip deployment of the system D3D compiler.
  --compiler-runtime        Deploy compiler runtime (Desktop only).
  --no-compiler-runtime     Do not deploy compiler runtime (Desktop only).
  --webkit2                 Deployment of WebKit2 (web process).
  --no-webkit2              Skip deployment of WebKit2.
  --json                    Print to stdout in JSON format.
  --list            Print only the names of the files copied.
                            Available options:
                             source:   absolute path of the source files
                             target:   absolute path of the target files
                             relative: paths of the target files, relative
                                       to the target directory
                             mapping:  outputs the source and the relative
                                       target, suitable for use within an
                                       Appx mapping file
  --verbose          Verbose level.

Qt libraries can be added by passing their name (-xml) or removed by passing
the name prepended by --no- (--no-xml). Available libraries:
bluetooth clucene concurrent core declarative designercomponents designer gui
clucene qthelp multimedia multimediawidgets multimediaquick network nfc opengl
positioning printsupport qml quick quickparticles script scripttools sensors
serialport sql svg test widgets winextras xml xmlpatterns

Arguments:
  [file]                    Binary or directory containing the binary.