Python Extension fails to select Anaconda base interpreter on Windows 11 ("Invalid Python interpreter" / UI selection ignored)

[abtxph01]

Environment Details

• OS: Windows 11
• VS Code Python Extension Version: ms-python.python-2026.4.0
• Anaconda Location: C:\Users\username\anaconda3 (Python 3.13)

Description

Selecting the global Anaconda base interpreter via Python: Select Interpreter fails to bind to active Python files. The selection in the UI is silently ignored or rejected as an invalid interpreter.

Expected Behavior

Selecting base (3.13.9) or setting python.defaultInterpreterPath to the global Anaconda installation should activate the environment for all workspace files, linting, and debugging.

Actual Behavior

1. Status bar remains yellow with "No Python environment is set for this resource".
2. Clicking base (3.13.9) or base (3.13.9.final.0) in the interpreter picker does nothing (selection is not saved).
3. In earlier attempts, selecting the executable threw the UI error:

   An Invalid Python interpreter is selected, please try changing it to enable features such as IntelliSense, linting, and debugging.

4. Launching VS Code directly from Anaconda Prompt (code .) works temporarily by populating CONDA_PREFIX, but opening individual .py files breaks environment detection again.

Extension Output Channel Logs

2026-07-30 17:21:50.391 [warning] Environment discovery completed but no Python environments were found.
2026-07-30 17:21:50.394 [info] No Python environment is set for this resource.
2026-07-30 17:22:01.248 [error] Failed to execute file in terminal [Error: Invalid arguments to run in terminal at t.runInTerminal (c:\Users\username\.vscode\extensions\ms-python.python-2026.4.0-win32-x64\out\client\extension.js:2:458958)...]
2026-07-30 17:23:16.570 [info] Active interpreter [global]:  C:\Users\username\anaconda3\python.exe
2026-07-30 17:23:16.571 [info] No Python environment is set for this resource.

[eleanorjboyd]

Thanks for the detailed report. This behavior appears to be owned by the Python Environments extension rather than the Python extension. Could you please open an issue at https://github.com/microsoft/vscode-python-environments/issues/new and link this discussion?

Please include your installed ms-python.vscode-python-envs version, the Python Environments output channel logs at Trace level, and the output from Python Environments: Run Python Environment Tool (PET) in Terminal → Search all. It would also help to clarify whether this occurs in a no-folder window or for a file outside the open workspace.