WinError 10054 when debugging Python code

[johnmbarrett]

Apologies if this is the wrong repo to report this in, but I am running into an issue where the Python debugger in VS Code consistently crashes with WinError 10054 when debugging certain code.

Steps to reproduce

1. Install the attached environment file
2. Set the VS Code Interpreter to the newly created environment (Ctrl+Shift+P -> Python: Select Interpreter)
3. Create a new file with the following code:

import numpy as np

np.cov(np.random.random(size=(50,41)),rowvar=False)

print('hello, world!')

4). Attempt to debug the file (Run and Debug side panel -> ▷ Python Debugger: Current File)

Expected behaviour

The script prints "hello, world!"

Actual behaviour

The script exits silently

Additional info

If you place a break point on or before line 3, the debugger runs up to the break point. The debugger exits silently if you attempt to continue past/step over line 3. If you highlight line 3, right-click, and select "Evaluate in Debug Console", the following error message is printed to the debug console:

[WinError 10054] An existing connection was forcibly closed by the remote host

This is not a stochastic error. It happens every time. It is not an issue with the script itself, nor the conda environment, as when I run it from the command prompt (outside of VS Code) it runs fine.

Environment info:

VS Code Version: 1.107.1 (user setup)
Commit: 994fd12f8d3a5aa16f17d42c041e5809167e845a
Date: 2025-12-17T14:15:14.850Z
Electron: 39.2.3
ElectronBuildId: 12895514
Chromium: 142.0.7444.175
Node.js: 22.21.1
V8: 14.2.231.21-electron.0
OS: Windows_NT x64 10.0.19045
Python extension version: 2025.20.1
Python Debugger extension version: 2025.18.0
Python Environments extension version 1.14.0
Pylance extension version: 2025.10.4
Python version: 3.12.12
conda version: 24.7.1

Hopefully that's all the relevant info. If you need any more information please let me know. Or if I should report this elsewhere please let me know which repo would be most appropriate.

[rchiodo]

This works fine for me.

Can you enable logging (add "logToFile": true in your launch.json) and try again? Log files will be written to where the vscode-python-debugger extension is installed.

[johnmbarrett]

Thanks for your response. I am still experiencing the error as of today (01/26/2026). The log files are attached. The error message in my original post appears in file debugpy.adapter-18152.log at line D+00004.797.

debugger.vscode_14deed7e-5f85-4ae0-940a-45eda52f510f.log
debugpy.adapter-18152.log
debugpy.launcher-12320.log
debugpy.pydevd.14244.log
debugpy.server-14244.log

[rchiodo]

Can you try this same thing in a newly created workspace? Your debug request shows a LOT of breakpoints, maybe that's messing something up. Otherwise the log looks like it just quits in the middle of trying to read the threads.

[rchiodo]

Hmm, the log says this too:

I+00004.125: Debuggee[PID=14244] exited with code 3228369023

That I believe is C06D007F, which comes out as a C++ exception. So likely the numpy code is crashing for some reason. You might also try reinstalling numpy or upgrading it.

[johnmbarrett]

Same thing in a newly created workspace (File -> New Window -> Open Folder, folder chosen is not one associated with an existing workspace). New logs are attached.

debugger.vscode_0323d887-32d2-45f6-a6b7-1c4575a2a3f3.log
debugpy.adapter-29920.log
debugpy.launcher-31520.log
debugpy.pydevd.4296.log
debugpy.server-4296.log

The test script runs fine from the VS Code terminal without debugging, which argues against an issue with numpy. Interestingly, it only runs in a Command Prompt terminal, not a PowerShell one, but the PowerShell terminal does not print any useful error message (just a little red dot next to the command).

Here is the Command Prompt output:

(base) C:\Users\jmb9770\Documents\Python\test>conda activate test

(test) C:\Users\jmb9770\Documents\Python\test>python test.py
hello, world!

(test) C:\Users\jmb9770\Documents\Python\test>"C:\Users\jmb9770\.conda\envs\test\python.exe" "c:\Users\jmb9770\.vscode\extensions\ms-python.debugpy-2025.18.0-win32-x64\bundled\libs\debugpy\launcher" "49480" "--" "C:\Users\jmb9770\Documents\Python\test\test.py"
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "c:\Users\jmb9770\.vscode\extensions\ms-python.debugpy-2025.18.0-win32-x64\bundled\libs\debugpy\launcher\__main__.py", line 92, in <module>
    main()
  File "c:\Users\jmb9770\.vscode\extensions\ms-python.debugpy-2025.18.0-win32-x64\bundled\libs\debugpy\launcher\__main__.py", line 48, in main
    launcher.connect(host, port)
  File "c:\Users\jmb9770\.vscode\extensions\ms-python.debugpy-2025.18.0-win32-x64\bundled\libs\debugpy\launcher/../..\debugpy\launcher\__init__.py", line 28, in connect
    sock.connect((host, port))
ConnectionRefusedError: [WinError 10061] No connection could be made because the target machine actively refused it

The third command line is what is run in PowerShell when I launch my Python debugging configuration.

[rchiodo]

Debugpy is going to cause more things to be analyzed, causing numpy to load more dlls. That's likely the root cause. The debuggee crashing with that exception is why the WinError 10054 is occurring.

[rchiodo]

Or you could try attaching a C++ debugger to the debuggee when it's running under debugpy. That should let you break when the C++ exception is thrown and get a callstack for where the problem is.

[johnmbarrett]

Note sure if I'm attaching it to the wrong PID (I'm attaching to the one whose description matches the PowerShell command that launched the Python debugger), but this all I get out of VS Code's C++ debugger (launch.json > Add Configuration... > {} C/C++: (Windows) Attach, all default options) when I attach it:

------------------------------------------------------------------------------
You may only use the C/C++ Extension for Visual Studio Code with Visual Studio
Code, Visual Studio or Visual Studio for Mac software to help you develop and
test your applications.
------------------------------------------------------------------------------
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\test\python.exe'. Symbols loaded.
python.exe (33896): Loaded 'C:\Windows\System32\ntdll.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\kernel32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\KernelBase.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\ucrtbase.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\python312.dll'. Symbols loaded.
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\test\vcruntime140.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\ws2_32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\version.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\rpcrt4.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\msvcrt.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\bcrypt.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\advapi32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\sechost.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\zlib.dll'. Module was built without symbols.
python.exe (33896): Loaded 'C:\Windows\System32\umppc20309.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\CsXumd64_20309.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\bcryptprimitives.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\python3.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\DLLs\_wmi.pyd'. 
python.exe (33896): Loaded 'C:\Windows\System32\oleaut32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\msvcp_win.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\combase.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\propsys.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\test\vcruntime140_1.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\DLLs\_socket.pyd'. 
python.exe (33896): Loaded 'C:\Windows\System32\IPHLPAPI.DLL'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\DLLs\select.pyd'. 
python.exe (33896): Loaded 'C:\Windows\System32\ole32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\gdi32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\win32u.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\gdi32full.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\user32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\imm32.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\kernel.appcore.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\uxtheme.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\clbcatq.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\amsi.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\userenv.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\profapi.dll'. 
python.exe (33896): Loaded 'C:\Windows\System32\ScriptControl64_20309.dll'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\test\DLLs\_ctypes.pyd'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\Library\bin\ffi-8.dll'. Module was built without symbols.
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\DLLs\_bz2.pyd'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\Library\bin\libbz2.dll'. Module was built without symbols.
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\DLLs\_lzma.pyd'. 
python.exe (33896): Loaded 'C:\Users\jmb9770\.conda\envs\unimanual\Library\bin\liblzma.dll'. Module was built without symbols.
python.exe (33896): Loaded 'C:\Windows\System32\mswsock.dll'. 
The program '[33896] python.exe' has exited with code -1 (0xffffffff).