Anaconda 2020.02 on Windows 10 64, problems with navigator

Question

I installed a fresh Anaconda version 2020.02 on my Windows 10 64, when I run anaconda-navigator script from Anaconda Prompt, I get this error:

    (base) PS C:\Users\Alessio> anaconda-navigator
    PySide2/__init__.py: Unable to import shiboken2 from D:\Anaconda3\Scripts, 
    D:\Anaconda3\python37.zip, D:\Anaconda3\DLLs, D:\Anaconda3\lib, D:\Anaconda3, 
    C:\Users\Alessio\AppData\Roaming\Python\Python37\site-packages, D:\Anaconda3\lib\site-packages, 
    D:\Anaconda3\lib\site-packages\win32, D:\Anaconda3\lib\site-packages\win32\lib, 
    D:\Anaconda3\lib\site-packages\Pythonwin
    Traceback (most recent call last):
    File "D:\Anaconda3\lib\site-packages\qtpy\__init__.py", line 204, in <module>
    from PySide import __version__ as PYSIDE_VERSION  # analysis:ignore
    ModuleNotFoundError: No module named 'PySide'

    During handling of the above exception, another exception occurred:

    Traceback (most recent call last):
    File "D:\Anaconda3\Scripts\anaconda-navigator-script.py", line 6, in <module>
      from anaconda_navigator.app.main import main
    File "D:\Anaconda3\lib\site-packages\anaconda_navigator\app\main.py", line 22, in <module>
      from anaconda_navigator.utils.conda import is_conda_available
    File "D:\Anaconda3\lib\site-packages\anaconda_navigator\utils\__init__.py", line 15, in <module>
      from qtpy.QtGui import QIcon
    File "D:\Anaconda3\lib\site-packages\qtpy\__init__.py", line 210, in <module>
      raise PythonQtError('No Qt bindings could be found')
      qtpy.PythonQtError: No Qt bindings could be found

Running pip freeze the versions of PySide2 and shiboken2 are the same:

• shiboken2: 5.14.2
• PySide2: 5.14.2

but I notice that PySide is missing, and is impossible to install manually because of Python interpreter level

maybe have to reinstall qtpy?

Any idea?

Ok, solved I had first to remove.condarc file in my home directory and run

conda update conda
conda update --all

but had still the same problem, finally i run

pip install --upgrade --force-reinstall pyqt5
pip install --upgrade --force-reinstall pyside2

And now is working

Answer 1

I know the question has a fix that worked for you @Alex, but I wanted to post what worked for me and I think it should be "safer" than what you posted since it doesn't use pip.

On a fresh install of Anaconda 2020-02 x86_64 I did the following:

conda update conda
conda update anaconda
conda install -c conda-forge pyside2

After the above I was able to start anaconda-navigator without any issues.

Hope this helps someone in the future!