Can't load openCV when not in install dir with Windows 10

[bebertii]

Expected behaviour

I have installed opencv-python with pip install opencv-python. with python 3.7.4 on an up-to-date Win10 64b.
openCV does work when the shell is on the install dir ('C:\Users\Gros\AppData\Local\Programs\Python\Python37')

Actual behaviour

But if I try to run a script outside of the install dir without having previously imported cv2 from the install dir, I'll have an error :
=========== RESTART: d:\Dropbox\2020\cours\2nde\pointage_video.py =========== Traceback (most recent call last): File "d:\Dropbox\2020\cours\2nde\pointage_video.py", line 15, in <module> import cv2 ImportError: DLL load failed: Le module spécifié est introuvable.

I added some folders to path :
C:\Users\Gros\AppData\Local\Programs\Python\Python37\Lib\site-packages\cv2 C:\Users\Gros\AppData\Local\Programs\Python\Python37\Lib C:\Users\Gros\AppData\Local\Programs\Python\Python37\Lib\site-packages C:\Users\Gros\AppData\Local\Programs\Python\Python37\Scripts C:\Users\Gros\AppData\Local\Programs\Python\Python37

No change.

[skvark]

There's no need to add anything to the PATH. You should create a fresh virtual environment and install opencv-python there. If it works in the virtual environment then your global Python installation has probably some conflicting cv2 installation.

If that doesn't work, then you have some dependency missing. Please read the FAQ and check that you have all the dependencies installed: https://github.com/skvark/opencv-python#frequently-asked-questions

[bebertii]

I'm sorry but I don't understand why ther would be a dependancy problem which prevent open-cv from working outside the install dir : it does work, but nor from anywhere.
And I still have the problem with a new virtual env. Below, I pasted what appened just after creating my new virtualenv :

`(python_env) C:\Users\Gros\python_env\Scripts>pip install opencv-python matplotlib pygame
Collecting opencv-python
Downloading https://files.pythonhosted.org/packages/a3/50/04d0669afe884f137c2f490642756e8c4a658254300a9eaf253d1e643085/opencv_python-4.1.0.25-cp37-cp37m-win_amd64.whl (37.3MB)
|████████████████████████████████| 37.4MB 6.8MB/s
Collecting matplotlib
Using cached https://files.pythonhosted.org/packages/1a/c0/69e3f695d7384012e90be1e16570c08953baae00fd98094179ef87c7d5a2/matplotlib-3.1.1-cp37-cp37m-win_amd64.whl
Collecting pygame
Using cached https://files.pythonhosted.org/packages/ed/56/b63ab3724acff69f4080e54c4bc5f55d1fbdeeb19b92b70acf45e88a5908/pygame-1.9.6-cp37-cp37m-win_amd64.whl
Collecting numpy>=1.14.5 (from opencv-python)
Downloading https://files.pythonhosted.org/packages/26/26/73ba03b2206371cdef62afebb877e9ba90a1f0dc3d9de22680a3970f5a50/numpy-1.17.0-cp37-cp37m-win_amd64.whl (12.8MB)
|████████████████████████████████| 12.8MB 3.2MB/s
Collecting python-dateutil>=2.1 (from matplotlib)
Using cached https://files.pythonhosted.org/packages/41/17/c62faccbfbd163c7f57f3844689e3a78bae1f403648a6afb1d0866d87fbb/python_dateutil-2.8.0-py2.py3-none-any.whl
Collecting cycler>=0.10 (from matplotlib)
Using cached https://files.pythonhosted.org/packages/f7/d2/e07d3ebb2bd7af696440ce7e754c59dd546ffe1bbe732c8ab68b9c834e61/cycler-0.10.0-py2.py3-none-any.whl
Collecting kiwisolver>=1.0.1 (from matplotlib)
Using cached https://files.pythonhosted.org/packages/c6/ea/e5474014a13ab2dcb5056608e0716c600c3d8a8bcffb10ed55ccd6a42eb0/kiwisolver-1.1.0-cp37-none-win_amd64.whl
Collecting pyparsing!=2.0.4,!=2.1.2,!=2.1.6,>=2.0.1 (from matplotlib)
Downloading https://files.pythonhosted.org/packages/11/fa/0160cd525c62d7abd076a070ff02b2b94de589f1a9789774f17d7c54058e/pyparsing-2.4.2-py2.py3-none-any.whl (65kB)
|████████████████████████████████| 71kB 4.5MB/s
Collecting six>=1.5 (from python-dateutil>=2.1->matplotlib)
Using cached https://files.pythonhosted.org/packages/73/fb/00a976f728d0d1fecfe898238ce23f502a721c0ac0ecfedb80e0d88c64e9/six-1.12.0-py2.py3-none-any.whl
Requirement already satisfied: setuptools in c:\users\gros\python_env\lib\site-packages (from kiwisolver>=1.0.1->matplotlib) (41.0.1)
Installing collected packages: numpy, opencv-python, six, python-dateutil, cycler, kiwisolver, pyparsing, matplotlib, pygame
Successfully installed cycler-0.10.0 kiwisolver-1.1.0 matplotlib-3.1.1 numpy-1.17.0 opencv-python-4.1.0.25 pygame-1.9.6 pyparsing-2.4.2 python-dateutil-2.8.0 six-1.12.0

(python_env) C:\Users\Gros\python_env\Scripts>python "d:\Dropbox\2020\cours\2nde\pointage_video.py"
pygame 1.9.6
Hello from the pygame community. https://www.pygame.org/contribute.html
Traceback (most recent call last):
File "d:\Dropbox\2020\cours\2nde\pointage_video.py", line 15, in
import cv2
ImportError: DLL load failed: Le module spécifié est introuvable.

(python_env) C:\Users\Gros\python_env\Scripts>python
Python 3.7.4 (tags/v3.7.4:e09359112e, Jul 8 2019, 20:34:20) [MSC v.1916 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.

import cv2
import os
os.getcwd()
'C:\Users\Gros\python_env\Scripts'
^Z

(python_env) C:\Users\Gros\python_env\Scripts>`

The script I tried to load uses opencv, pygame and matplotlib. Only opencv can't be loaded. However, just after I'm able to load it, because I'm on the virtualenv dir.

[skvark]

Check the cv2.so with dependency walker (see README). Your environment is somehow broken.

[bebertii]

You are right, problem solved after reinstalling Win10, everything went fine.
Thanks !