Python : Fix DLL load failed while importing ...

This error DLL load failed while importing ... can have many causes like conflicts with the already installed packages, and also it can break your current environment.

>>> import PyQt6
>>> from PyQt6.QtCore import QUrl
Traceback (most recent call last):
  ...
ImportError: DLL load failed while importing QtCore: The specified module could not be found.

You can see I used to reinstall the PyQt6 python package with this argument --ignore-installed:

pip3 install PyQt6 --user --ignore-installed
Collecting PyQt6
  ...
Installing collected packages: PyQt6-Qt6, PyQt6-sip, PyQt6
  WARNING: The scripts pylupdate6.exe and pyuic6.exe are installed in
  ...
  which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed PyQt6-6.4.0 PyQt6-Qt6-6.4.2 PyQt6-sip-13.4.0

The --ignore-installed option for the pip package manager was first introduced in version 6.0, which was released in April 2014.

The old install give me this error and when I try to use I got this:

>>> from PyQt6 import *
>>> dir(PyQt6)
['__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__']

Now after I reinstall with this option the result is good:

>>> import PyQt6
>>> from PyQt6 import QtCore
>>> dir(PyQt6)
['QtCore', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__path__', '__spec__', 'sip']
>>> from PyQt6.QtCore import QUrl