Thonny IDE throws AssertionError on startup

Question

I have faced error while opening the Thonny Ide.

ERROR: Internal error
Traceback (most recent call last):
  File "C:\Program Files (x86)\Thonny\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\running.py", line 356, in cmd_stop_restart
    self.restart_backend(True)
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\running.py", line 458, in restart_backend
    self._proxy = backend_class(clean)
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\running.py", line 1036, in __init__
    CPythonProxy.__init__(self, executable)
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\running.py", line 624, in __init__
    self._start_new_process()
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\running.py", line 764, in _start_new_process
    debug("Starting the backend: %s %s", cmd_line, get_workbench().get_cwd())
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\workbench.py", line 1252, in get_cwd
    return normpath_with_actual_case(os.path.expanduser("~"))
  File "C:\Program Files (x86)\Thonny\lib\site-packages\thonny\common.py", line 212, in normpath_with_actual_case
    assert os.path.isabs(name)
AssertionError

OS: Windows 7 64-bit
Python: Python 3.7(94bit)
Thonny:3.1.2

so you are trying to install thonny separately and not the thonny python bundle — Duck_dragon, Apr 10 '19 at 07:58
Is your home directory (under) a network path? Current Thonny version can't handle them (https://github.com/thonny/thonny/issues/711). This will be fixed in the next version. — Aivar, Apr 10 '19 at 09:12

score 1 · Answer 1 · answered May 21 '19 at 14:26

Open %APPDATA%\Thonny\configuration.ini (or wherever your IDE config is)

Scroll down to [run] section and check parameter working_directory.

Make sure something meaningful is set there, e.g. C:\ should do the trick (no double backslahes, quotes, etc..).

I had the same issue. For some reason only word lib was there. Modifying this parameter to a proper filesystem path fixed it in my case.

score 0 · Answer 2 · answered May 01 '19 at 22:26

Something has corrupted the current instance of your Thonny installation at the backend.

You will first need to completely uninstall Thonny and then remove any imprints of Thonny from your computer's registry.

Then reinstall Thonny and open Thonny IDE. Hope this helps.

score -1 · Answer 3 · answered Apr 17 '21 at 06:41

-1

I also faced this issue, for me it was due to Antivirus, just disabling Auto Containment fixed the issue, Hope this helps.

answered Apr 17 '21 at 06:41

Sachin Puri

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Thonny IDE throws AssertionError on startup

3 Answers3