Error “could not find or load the Qt platform plug

Question

I am getting the error "could not find or load the Qt platform plugin windows" while using matplotlib in PyCharm.

How can I solve this?

Answer 1

I had the same problem with Anaconda3 4.2.0 and 4.3.0.1 (64-bit). When I tried to run a simple program that uses matplotlib, I got this error message:

This application failed to start because it could not find or load the Qt platform plugin "windows"

Reinstalling the application may fix this problem.

Reinstalling didn't fix it.

What helped was this (found here): Look for the Anaconda directory and set the Library\plugins subdir (here c:\ProgramData\Anaconda3\Library\plugins) as environment variable QT_PLUGIN_PATH under Control Panel / System / Advanced System Settings / Environment Variables.

After setting the variable you might need to restart PyCharm, if the change does not have an immediate effect.

Et voilà!

Update: Even though after that the command line Python worked, TexWorks (which uses Qt as well) displayed an error message very much like it. Setting the QT_PLUGIN_PATH to the directory containing TexWorks' Qt DLLs (here C:\Users\chris\AppData\Local\Programs\MiKTeX 2.9\miktex\bin\x64) fixed the problem for both programs.

Answer 2

I found that this was being caused by having the MiKTeX binaries in my PATH variable; and the wrong Qt dll's were being found. I just needed to re-arrange the PATH entries.

(Dependency Walker is such a useful tool.)

Answer 3

If you want to visualize your matplotlibs in an alternative way, use a different backend that generates the graphs, charts etc.

import matplotlib matplotlib.use('TKAgg')

This worked for me.

Answer 4

If installed PyQt5 and PySide2, I solved problem

Copy the following files

\Anaconda3\Lib\site-packages\PySide2\plugins\platforms\qminimal.dll
\Anaconda3\Lib\site-packages\PySide2\plugins\platforms\qoffscreen.dll
\Anaconda3\Lib\site-packages\PySide2\plugins\platforms\qwindows.dll

to

\Anaconda3\Library\plugins\platforms\

Answer 5

I tried the following in Anaconda prompt, and it solved this problem:

conda remove qt

conda remove pyqt

conda install qt

conda install pyqt

Answer 6

On Windows

1- Copy the folder plastforms: C:\Users\%USERNAME%\AppData\Roaming\pyinstaller\bincache00_py35_64bit\pyqt5\qt\plugins\platforms

2- Paste the folder platform into the folder location of the file .exe

Example: c:\MyFolder\yourFile.exe c:\MyFolder\platforms