PyInstaller; "could not find or load the Qt platform plugin "windows"

Question

My PyInstaller spec:

# -*- mode: python -*-

block_cipher = None


a = Analysis(['test.py'],
             pathex=['C:\\Users\\admin\\compile'],
             binaries=[('C:\\Python361\\Lib\\site-packages\\PyQt5\\Qt\\plugins\\platforms\\qwindows.dll', 'qwindows.dll')],
             datas=[],
             hiddenimports=[],
             hookspath=[],
             runtime_hooks=[],
             excludes=[],
             win_no_prefer_redirects=False,
             win_private_assemblies=False,
             cipher=block_cipher)

pyz = PYZ(a.pure, a.zipped_data,
             cipher=block_cipher)
exe = EXE(pyz,
          a.scripts,
          a.binaries,
          a.zipfiles,
          a.datas,
          name='test',
          debug=False,
          strip=False,
          upx=False,
          runtime_tmpdir=None,
          console=False , icon='icon.ico')

So I have ran into the problem where I will compile my PyQt5 5.8.2 (with Python 3.6.1) program with the latest version of PyInstaller from pip, and it works! The statically linked, onefile executable works on my computer with all the Qt stuff on it.

But then I test it on any computer or virtual machine that doesn't have the Qt environment set up already, and it crashes on start because of the "could not find or load the Qt platform plugin 'windows'" error. If you look at the spec you'll notice that I attempted to store the DLL in the binary list manually so PyInstaller would store it in the executable, but that didn't work.

I would like to know what I need to change so that I can compile my application without having to do something like include the platforms folder in the folder with the executable (I want everything to be in the executable), would it be as simple as a change in the spec file that I didn't realize so that it stores the DLL in the executable?

By the way, this is not a duplicate. I looked at some of the other questions and all of them were either for a different type of application or the solution was to downgrade or store the DLL in the folder and I can't do either of those.

EDIT: So I changed it to onedir just to see if it was even in there, and qwindows.dll is inside of the folder. There is also a qt5_plugins folder which has a platforms folder which also has a qwindows.dll. So how is it not detecting the dll??

Answer 1

There seem to be two solutions, the first one worked fine for me:

• copy platform directory to directory of your executable. You'll find the platform directory at a location like c:\Users\<username>\envs\<environmentname>\Library\plugins\platforms or

• Upgrade to a newer version of pyqt: conda install -c anaconda pyqt

Use the second option with care: Do not try to use pip for pyqt installation if you have a conda environment, this might break your conda installation: https://github.com/ContinuumIO/anaconda-issues/issues/1970

Answer 2

Got the same problem with PyQt6 6.0.3 and PyInstaller 4.3.

First a tried a one-folder bundle which worked fine after adding the platform and style plugins to the binaries list and PyQt6.sip to the hiddenimports one (The latter may be need only if using PyQt6).

When i tried the one-file bundle i got the platform plugin error. First i checked if the files are being copied by looking in the temp folder where the bundle is unpacked during runtime (with the error dialog open) and all the DLL's were there. When i copied then to the same folder as the executable it worked fine, the problem was Qt wasn't finding them in the temp folder.

I found the solution reading about QT_PLUGIN_PATH in the Qt documentation then looking in this PyInstaller commit.

After adding the plugins' DLLs just add a runtime hook to set QT_PLUGIN_PATH.

Also if using UPX the plugins' DLLs need to be added to the upx_exclude list.

Here's the hook and spec file i used, with default options removed:

pyQtHook.py

import os
import sys
from pathlib import Path

os.environ['QT_PLUGIN_PATH'] = str( Path( sys._MEIPASS ) / 'PyQt6/Qt6' )

oneFile.spec

from pathlib import Path

root = Path.cwd()
qtRoot = root / 'env/Lib/site-packages/PyQt6/Qt6'

analysis = Analysis(
    scripts = [
        root / 'src/main.py',
    ],
    pathex = [
        root,
        qtRoot / 'bin',
    ],
    binaries = [
        ( qtRoot / 'plugins/platforms/qwindows.dll', 'PyQt6/Qt6/plugins/platforms' ),
        ( qtRoot / 'plugins/styles/qwindowsvistastyle.dll', 'PyQt6/Qt6/plugins/styles' ),
    ],
    hiddenimports =[
        'PyQt6.sip',
    ],
    runtime_hooks = [
        'pyQtHook.py',
    ],
)

pyz = PYZ( analysis.pure, analysis.zipped_data )

exe = EXE(
    pyz,
    analysis.scripts,
    analysis.binaries,
    analysis.zipfiles,
    analysis.datas,
    name = 'MyApp',
    console = False,
    upx = True,
    upx_exclude = [
        'qwindows.dll',
        'qwindowsvistastyle.dll',
    ],
)

Answer 3

I had an issue where my python code worked fine, but the compiled .exe file would provide the "could not find or load the Qt platform plugin windows" problem. I fixed the problem by copying the ~PyQt5\Qt\plugins\platforms folder from the program's directory, generated by using pyinstaller --onedir main.py, to the folder holding the .exe file.

It seems that in my case the only way "helping" my program detect the required .dlls was having the platforms folder next to the main.exe. Pasting the platforms folder to the program's directory after using pyinstaller --onefile main.py also makes the program work.

Answer 4

I just update my pyqt5 package to 5.10.1 and fix that.