After installing a Python version, default packages fail to install due to bad path to Python EXE

[camel-eon]

someuser@somepc MINGW64 ~/somepath
$ mise use python@3.12
mise Cannot parse Rekor public key with id cf1199155bddd051268d1f16ac5c0c75c009f6fb5a63f4177f8e18d7051e3fa0: Pkcs8 spki error : Ecdsa-P256 from der bytes to public key failed: unknown/unsupported algorithm OID: 1.2.840.10045.2.1
mise WARN  failed to install default python packages: failed to execute command: C:\Users\someuser\AppData\Local\mise\installs\python\3.12.13\bin/python -m pip install --upgrade -r C:\Users\someuser\.default-python-packages: Das System kann den angegebenen Pfad nicht finden. (os error 3)
python@3.12.13  install default packages                                                                               ✔
mise C:\Users\someuser\somepath\mise.toml tools: python@3.12.13

$ mise doctor
version: 2026.4.1 windows-x64 (2026-04-02)
shims_on_path: yes
self_update_available: yes

build_info:
  Target: x86_64-pc-windows-msvc
  Features: DEFAULT, NATIVE_TLS, OPENSSL, RUSTLS_NATIVE_ROOTS, SELF_UPDATE
  Built: Thu, 2 Apr 2026 10:54:51 +0000
  Rust Version: rustc 1.94.0 (4a4ef493e 2026-03-02)
  Profile: release

shell:
  (unknown)

aqua:
  baked in registry tools: 2273

dirs:
  cache: ~\AppData\Local\Temp\mise
  config: ~\.config\mise
  data: ~\AppData\Local\mise
  shims: ~\AppData\Local\mise\shims
  state: ~\.local\state\mise

config_files:
  ~\.config\mise\config.toml
  ~\Lokale Daten\Deep Learning\mise.toml

ignored_config_files: (none)

backends:
  aqua
  asdf
  cargo
  conda
  core
  dotnet
  forgejo
  gem
  github
  gitlab
  go
  npm
  pipx
  spm
  http
  s3
  ubi
  vfox

plugins:

toolset:
  core:java@25.0.2
  core:node@24.14.0
  core:python@3.12.13

path:
  ~\bin
  ~\scoop\apps\git\2.53.0\mingw64\bin
  ~\scoop\apps\git\2.53.0\usr\local\bin
  ~\scoop\apps\git\2.53.0\usr\bin
  ~\scoop\apps\git\2.53.0\usr\bin
  ~\scoop\apps\git\2.53.0\mingw64\bin
  ~\scoop\apps\git\2.53.0\usr\bin
  ~\bin
  C:\Windows\system32
  C:\Windows
  C:\Windows\System32\Wbem
  C:\Windows\System32\WindowsPowerShell\v1.0
  C:\Windows\System32\OpenSSH
  C:\Program Files\dotnet
  C:\Program Files\gsudo\Current
  C:\texlive\2025\bin\windows
  ~\AppData\Local\mise\installs\python\3.12.13
  ~\AppData\Local\mise\installs\java\25.0.2\bin
  ~\AppData\Local\mise\installs\node\24.14.0
  ~\AppData\Local\mise\shims
  ~\scoop\apps\git\current\cmd
  ~\scoop\shims
  ~\AppData\Local\UniGetUI\Chocolatey\bin
  ~\AppData\Local\Microsoft\WindowsApps
  ~\AppData\Local\Microsoft\WinGet\Links
  ~\AppData\Local\Microsoft\WinGet\Packages\Google.PlatformTools_Microsoft.Winget.Source_8wekyb3d8bbwe\platform-tools
  ~\AppData\Local\Programs\Microsoft VS Code\bin
  ~\Lokale Daten\Flutter\flutter\bin
  ~\AppData\Local\Programs\mongosh
  C:\Program Files (x86)\MongoDB CLI
  C:\Program Files\MongoDB\Tools\100\bin
  ~\scoop\apps\git\2.53.0\usr\bin\vendor_perl
  ~\scoop\apps\git\2.53.0\usr\bin\core_perl

env_vars:
  (none)

settings:

No problems found

The path to the Python binary is C:\Users\someuser\AppData\Local\mise\installs\python\3.12.13\python.exe and not C:\Users\someuser\AppData\Local\mise\installs\python\3.12.13\bin/python. So of course the file is not found. But why does it try to use the wrong path here?

(Also, I have no idea what the Rekor public key thing means...)

[ThinkOpenly]

This is not terribly helpful, but I'm seeing the same thing:

$ mise install
python@3.14.4   python --version                                                                                                                                                          ◟
mise ERROR Failed to install core:python@3.14.4: failed to execute command: ~/.local/share/mise/installs/python/3.14.4/bin/python --version: No such file or directory (os error 2)
mise ERROR Run with --verbose or MISE_VERBOSE=1 for more information

[ThinkOpenly]

I suggest changing the title of this discussion to something more alarming, like "Cannot install Python".

I have found maybe a few older versions work, like 3.13.1, perhaps because they are being built during installation.

[ThinkOpenly]

A little additional information. EVERY currently available precompiled version fails to install. The latest non-precompiled version at present is 3.13.6. That works for me.

[iki]

Steps to reproduce (on Windows)

> echo pywin32 > "%UserProfile%\.default-python-packages"

> mise use -g python@3.12
DEBUG Version: 2026.5.6 windows-x64 (2026-05-11)
...
DEBUG $ C:\_\.mise\python\3.12.13\bin/python -m pip install --upgrade -r C:\Users\iki\.default-python-packages
WARN  failed to install default python packages: failed to execute command: C:\_\.mise\python\3.12.13\bin/python -m pip install --upgrade -r C:\Users\iki\.default-python-packages: The system cannot find the path specified. (os error 3)
INFO  python@3.12.13                    ✓ installed

> C:\_\.mise\python\3.12.13\bin\python -m pip install --upgrade -r C:\Users\iki\.default-python-packages
The system cannot find the path specified.

> C:\_\.mise\python\3.12.13\python -m pip install --upgrade -r C:\Users\iki\.default-python-packages
Collecting pywin32 (from -r C:\Users\iki\.default-python-packages (line 1))
  Using cached pywin32-311-cp312-cp312-win_amd64.whl.metadata (10 kB)
Using cached pywin32-311-cp312-cp312-win_amd64.whl (9.5 MB)
Installing collected packages: pywin32
  WARNING: The scripts pywin32_postinstall.exe and pywin32_testall.exe are installed in 'C:\_\.mise\python\3.12.13\Scripts' which is not on PATH.
  Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed pywin32-311

Cause

On Windows, python.exe is directly in package directory, not in bin subdirectory.

Also it would make sense to use OS path separator \ instead of hardcoded /.

Possible solution

Search python executable in binaries collected for creating shims.
Use OS path separator.

WDYT @jdx?