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Bug: "Unable to handle" error when selecting Python interpreter from uv-managed .venv #25886

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Bug: "Unable to handle" error when selecting Python interpreter from uv-managed .venv#25886
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info-neededIssue requires more information from postertriage-neededNeeds assignment to the proper sub-team

Description

@camhelkuik
Cameron Helkuik (camhelkuik)
opened on Mar 27, 2026

Type: Bug

Environment

  • OS: Windows 11
  • Editor: Kiro (VS Code-based)
  • Python Extension version: v2026.4.0
  • Python: 3.13.5
  • Package manager: uv 0.11.1

Steps to Reproduce

  1. Create a new project using uv init
  2. Run uv venv and uv sync to create the virtual environment
  3. Open the project in the editor
  4. Ctrl + Shift + P → "Python: Select Interpreter"
  5. Choose "Enter interpreter path..." → "Find..."
  6. Navigate to .venv\Scripts\python.exe and select it

Expected Behavior

The interpreter should be set to .venv\Scripts\python.exe without errors.

Actual Behavior

Error message: "Unable to handle c:\Users[username]....venv\Scripts\python.exe"

The interpreter is not set. The .venv is valid and .venv\Scripts\python.exe --version returns Python 3.13.5 successfully from the terminal.

Workaround

Manually setting the interpreter path in .vscode/settings.json works:

{
    "python.defaultInterpreterPath": "${workspaceFolder}\\.venv\\Scripts\\python.exe"
}

Additional Info

The virtual environment was created by uv (v0.11.1). The issue appears to be with the interpreter picker UI, not the venv itself.

Extension version: 2026.4.0
VS Code version: Code 1.112.0 (07ff9d6178ede9a1bd12ad3399074d726ebe6e43, 2026-03-17T18:09:23Z)
OS version: Windows_NT x64 10.0.22631
Modes:

  • Python version (& distribution if applicable, e.g. Anaconda): 3.13.5
  • Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): System
  • Value of the python.languageServer setting: Default
User Settings

languageServer: "Pylance"

</p>
</details>

<details>
<summary>Installed Extensions</summary>

|Extension Name|Extension Id|Version|
|---|---|---|
|astronomic-theme|mys|0.9.2|
|bruno|bru|4.5.0|
|debugpy|ms-|2025.18.0|
|js-debug|ms-|1.112.0|
|js-debug-companion|ms-|1.1.3|
|json-sort-and-compare|far|0.0.6|
|python|ms-|2026.4.0|
|remote-wsl|ms-|0.104.3|
|ruff|cha|2026.38.0|
|vscode-js-profile-table|ms-|1.0.10|
|vscode-pylance|ms-|2026.1.1|
|vscode-python-envs|ms-|1.24.0|
</details>

<!-- generated by issue reporter -->

Activity

  1. github-actions
    added
    triage-neededNeeds assignment to the proper sub-team
    on Mar 27, 2026

  2. eleanorjboyd commented on Apr 3, 2026

    @eleanorjboyd
    Eleanor Boyd (eleanorjboyd)
    on Apr 3, 2026
    Member

    Two questions here:

    • Does this reproduce in official VS Code Stable/Insiders as well, or only in Kiro?
    • What do Python and Python Environments output channels show at Trace level during the failed selection?
  3. github-actions
    added
    info-neededIssue requires more information from poster
    on Apr 3, 2026
  4. Eleanor Boyd (eleanorjboyd)
    marked Unable to handle c:\Users\XXX\AppData\Local\Python\bin\python3.14.exe #25843 as a duplicate of this issue on Apr 3, 2026

  5. camhelkuik commented on Apr 6, 2026

    @camhelkuik
    Cameron Helkuik (camhelkuik)
    on Apr 6, 2026
    Author
    1. It appears that in the official VS Code Stable it does NOT reproduce. This issue only happens in Kiro.
    2. Here is the output channel when trying to select a python interpreter showing the Trace level :
    2026-04-06 10:32:18.143 [debug] Checking venv (ms-python.python:venv) for c:\Users\.....\.venv\Scripts\python.exe
2026-04-06 10:32:18.143 [debug] Failed to resolve venv env "c:\Users\.....\.venv\Scripts\python.exe": Error: Python Environment Tools (PET) failed after 3 restart attempts. Please reload the window or check the output channel for details. To debug, run "Python Environments: Run Python Environment Tool (PET) in Terminal" from the Command Palette.
2026-04-06 10:32:18.143 [debug] Failed to resolve env "c:\Users\.....\.venv\Scripts\python.exe": Error: Python Environment Tools (PET) failed after 3 restart attempts. Please reload the window or check the output channel for details. To debug, run "Python Environments: Run Python Environment Tool (PET) in Terminal" from the Command Palette.
2026-04-06 10:32:18.143 [debug] Manager venv (ms-python.python:venv) cannot handle c:\Users\.....\.venv\Scripts\python.exe
2026-04-06 10:32:18.143 [debug] Checking Conda (ms-python.python:conda) for c:\Users\.....\.venv\Scripts\python.exe
2026-04-06 10:32:18.143 [debug] Checking Global (ms-python.python:system) for c:\Users\.....\.venv\Scripts\python.exe
2026-04-06 10:32:18.144 [debug] Failed to resolve env "c:\Users\.....\.venv\Scripts\python.exe": Error: Python Environment Tools (PET) failed after 3 restart attempts. Please reload the window or check the output channel for details. To debug, run "Python Environments: Run Python Environment Tool (PET) in Terminal" from the Command Palette.
2026-04-06 10:32:18.144 [error] Unable to handle c:\Users\.....\.venv\Scripts\python.exe
    1. When I try to run: Python Environments: Run Python Environment Tool (PET) in Terminal in the command palette, Find All Environments:
    c:\Users\..\.kiro\extensions\ms-python.python-2026.4.0-universal\python-env-tools\bin\pet.exe find --verbose
&: The term 'c:\Users\..\.kiro\extensions\ms-python.python-2026.4.0-universal\python-env-tools\bin\pet.exe' is not recognized as a name of a cmdlet, function, script file, or executable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
    1. When I try to run Python Environments: Run Python Environment Tool (PET) in Terminal in the command palette, Resolve Environment:
    PS C:\Users\..\automate-everything-with-python\accessing-apis> & c:\Users\..\.kiro\extensions\ms-python.python-2026.4.0-universal\python-env-tools\bin\pet.exe resolve "C:\Users\..\automate-everything-with-python\accessing-apis\.venv\Scripts\python.exe"
&: The term 'c:\Users\..\.kiro\extensions\ms-python.python-2026.4.0-universal\python-env-tools\bin\pet.exe' is not recognized as a name of a cmdlet, function, script file, or executable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
  6. github-actions
    removed
    info-neededIssue requires more information from poster
    on Apr 6, 2026

  7. eleanorjboyd commented on Apr 22, 2026

    @eleanorjboyd
    Eleanor Boyd (eleanorjboyd)
    on Apr 22, 2026
    Member

    Closing this issue — it's a Kiro-specific PET binary issue, not a VS Code or extension bug.

    This is also a duplicate of microsoft/vscode-python-environments#1394 for the general "Unable to handle" class of issues.

    If you experience this in official VS Code (not Kiro), please file a new issue with output logs from the "Python Environments" output channel. Thanks!

  8. Eleanor Boyd (eleanorjboyd)
    closed this as completedon Apr 22, 2026
  9. github-actions
    added
    info-neededIssue requires more information from poster
    on Apr 22, 2026
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