A keyboardInterrupt happent when venv going start

[HECARIIA]

Type: Bug

Description
When running Python code that requires blocking input (e.g., input()) for the first time in a new shell, VS Code triggers an unexpected KeyboardInterrupt.
This issue only occurs inside a Python virtual environment (venv).
Running the same code a second time (and any subsequent times) works normally.

This behavior does not occur when using the system Python interpreter.
I am using the default "python" debug configuration provided by VS Code.

Steps to Reproduce

1. Open VS Code.

2. Create or activate a Python venv.

3. Run a simple blocking script, for example:

input("Enter something: ")

4. Observe that VS Code immediately raises a KeyboardInterrupt on the first run.

5. Run the same script again in the same shell.

6. The script works normally without interruption.

Expected Behavior
The script should wait for user input normally on the first run, just like it does on subsequent runs.

Actual Behavior

On the first execution in a new shell:

The program is interrupted automatically.

A KeyboardInterrupt is raised without any user action.

On second and later executions:

The script behaves normally and waits for input.

Additional Notes
The issue only appears when using a virtual environment.

The issue does not occur with the system Python interpreter.

I am using the default "python" launch configuration generated by VS Code.

ScreenShot_2026-01-09_04-46-44.mp4

Environment：

VS Code version: 1.108.0

Python extension version: 2025.21.2026010601

Operating System: Windows 11 25H2 26200.7462

Python version: python 3.14.2

Virtual environment type: venv

Shell used: PowerShell

Extension version: 2025.21.2026010601
VS Code version: Code 1.108.0 (94e8ae2b28cb5cc932b86e1070569c4463565c37, 2026-01-08T13:53:10.781Z)
OS version: Windows_NT x64 10.0.26200
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.14.2
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): System
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Pylance"

Installed Extensions

Extension Name	Extension Id	Version
autodocstring	njp	0.6.1
copilot-chat	Git	0.35.3
debugpy	ms-	2025.19.2025121701
even-better-toml	tam	0.21.2
js-debug	ms-	1.105.0
js-debug-companion	ms-	1.1.3
jupyter	ms-	2025.10.2026010601
jupyter-keymap	ms-	1.1.2
jupyter-renderers	ms-	1.3.2025062701
python	ms-	2025.21.2026010601
remote-containers	ms-	0.438.0
remote-explorer	ms-	0.5.0
remote-server	ms-	1.5.3
remote-ssh	ms-	0.122.0
remote-ssh-edit	ms-	0.87.0
remote-wsl	ms-	0.104.3
ruff	cha	2026.34.0
vscode-docker	ms-	2.0.0
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-language-pack-zh-hans	MS-	1.108.2026010709
vscode-pylance	ms-	2025.10.100
vscode-python-envs	ms-	1.15.13521015
vscode-remote-extensionpack	ms-	0.26.0

System Info

Item	Value
CPUs	13th Gen Intel(R) Core(TM) i7-13650HX (20 x 2803)
GPU Status	2d_canvas: enabled direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off trees_in_viz: disabled_off video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	31.63GB (18.07GB free)
Process Argv	--crash-reporter-id 57e8a3cf-b24b-44a7-a2da-975ff851ba3d
Screen Reader	no
VM	0%

A/B Experiments

vsliv368:30146709
binariesv615:30325510
nativeloc1:31344060
dwcopilot:31170013
dwoutputs:31242946
copilot_t_ci:31333650
e5gg6876:31282496
pythonrdcb7:31342333
6518g693:31436602
aj953862:31281341
6abeh943:31336334
envsactivate1:31353494
cloudbuttont:31379625
3efgi100_wstrepl:31403338
use-responses-api:31390855
je187915:31407605
ec5jj548:31422691
terminalsuggestenabled:31431119
cmp-ext-treat:31426748
cp_cls_c_966_ss:31442353
c0683394:31419495
478ah919:31426797
ge8j1254_inline_auto_hint_haiku:31427726
a5gib710:31434435
38bie571_auto:31426784
no_request_with_suggest:31435826
rename_enabled:31436409
7a04d226_do_not_restore_last_panel_session:31438103
anthropic_thinking_t:31432745
h0hdh950:31428394
cp_cls_c_1081:31443829
copilot-nes-callisto-trt:31434412
nowdiget:31442216
nes-slash-models-on:31441832
nes-set-to-on:31441941
a43f0576c:31442824

[mlcfr]

It's not a bug. You are trying to run Python code from an environment that you haven't activated first.

[HECARIIA]

It's not a bug. You are trying to run Python code from an environment that you haven't activated first.

I'm find this when I using matplotlib. If the environment haven't activate, it should report error immediately, but it doesn't.
So I think environment isn't the reason. Besides, not run in the right environment should not report "KeyboardInterrupt", which should be reported when I press "CTRL + C", but not when run the code.

[HECARIIA]

It's not a bug. You are trying to run Python code from an environment that you haven't activated first.

Thank for you help, I have understand what happend when I use "Run by Python".
When I click this button, it open a new terminal and run the code, but terminal run "& .\Activate.ps1" when the python code is running, and this will creat a KeyboardInterrupt to stop python.
I still think this should be a bug.

[sagar-aps-MaMaTa]

This happened after the last update. Running any debug command in any 'new' terminal first goes to KeyboardInterrupt.

Before the update, this worked quite smoothly. The debug commands do 'try' to activate the environment but then an Interrupt is immediately sent.

Here is an example of the command that stops at first run but works at second.

The issue is worse when youtry to run TWO debugs at the same time. The Keyboard Interrupt kills the FIRST debug terminal.

& 'C:\Users\apshankar\Documents\Python_Virtual_envs\Cognite_DataScience_py312\Scripts\python.exe' 'c:\Users\apshankar\.vscode\extensions\ms-python.debugpy-2025.18.0-win32-x64\bundled\libs\debugpy\launcher' '64571' '--' '-m' 'motor_current_rise.cli' 'run' '--ptt' 'MotorCurrentDrift' '--current-key' 'PT6.I.''input_timeseries''' '--label-key' 'PT9.I.''target_time_series''' '--granularity' '1h' '--aggregation' 'average' '--label-granularity' '1h' '--label-aggregation' 'max' '--shift-hours' '6' '--tuner' 'optuna' '--tune-trials' '130' '--log-level' 'INFO' '--log-file' 'C:\Users\apshankar\Documents\Sagar/Lab_AlgoTestBed/motor_current_rise/motor_current_rise/data/outputs/run_all.log' '--output-xlsx' 'C:\Users\apshankar\Documents\Sagar/Lab_AlgoTestBed/motor_current_rise/motor_current_rise/data/outputs/all_assets_optuna.xlsx'

[HECARIIA]

Look this, VSCode try to starting venv when code is running:

And it need 4 seconds to start:

[HECARIIA]

It looks like this bug is fixed now. It still happens when you use Code Runner, but that's a different issue.

[rfernand2]

As of Feb-22-2026, I am still seeing this bug, which I think has been around since Dec-2025. It only happens every 1 in about 10 runs. Here a stack trace:
INFO: Uvicorn running on http://localhost:5000 (Press CTRL+C to quit)
INFO: Started reloader process [16316] using StatReload
INFO: DEBUG=True, TESTER_LOGIN=True
INFO: Started server process [28324]
INFO: Waiting for application startup.
INFO: Application startup complete.
ERROR: Traceback (most recent call last):
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\asyncio\runners.py", line 118, in run
return self._loop.run_until_complete(task)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\asyncio\base_events.py", line 654, in run_until_complete
return future.result()
^^^^^^^^^^^^^^^
asyncio.exceptions.CancelledError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\site-packages\uvicorn_compat.py", line 30, in asyncio_run
return runner.run(main)
^^^^^^^^^^^^^^^^
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\asyncio\runners.py", line 123, in run
raise KeyboardInterrupt()
KeyboardInterrupt

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\site-packages\starlette\routing.py", line 701, in lifespan
await receive()
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\site-packages\uvicorn\lifespan\on.py", line 137, in receive
return await self.receive_queue.get()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "D:\Users\rfern\AppData\Local\anaconda3\envs\sessions\Lib\asyncio\queues.py", line 158, in get
await getter
asyncio.exceptions.CancelledError

INFO: Stopping reloader process [16316]
PS D:\github\sessions4>

[loleczkowo]

I also experinced this issue and i found that the problem for me was setting both Python environment and interpreter to a venv.
Setting the Python enviroment to the actuall python fixed it for me.

[yhlam]

Got the same problem. Setting python.useEnvironmentsExtension to true solves my problem. I think somehow both the python environment and interpreter settings attempted to activate the venv. The second activation interrupted the running script.

[Erlonealpha]

Got the same problem. Setting python.useEnvironmentsExtension 到 true solves my problem. I think somehow both the python environment and interpreter settings attempted to activate the venv. The second activation interrupted the running script.

Thanks, It works for me.

[optinsoft]

I have the same problem. With conda.