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FixMyError.net
Windows New Added 26 September 2026

Python was not found; run without arguments to install from the Microsoft Store

Windows ships app execution aliases for python.exe and python3.exe that open the Store, and they sit early enough in PATH to shadow a real installation. Anything that shells out to python hits the stub, including build scripts and node-gyp, so an interpreter you can see on disk appears to be missing.

Quick fix

Read the commands before running them. Anything that restarts a service, deletes data or changes permissions should be tried on a non-production system first.

Quick fix
# What is actually being found, and what is installed
where.exe python
where.exe python3
py -0p                    # every interpreter the launcher knows about

# The stubs live here, and they are not real interpreters
dir "$env:LOCALAPPDATA\Microsoft\WindowsApps\python*.exe"

# Turn them off: Settings, Apps, Advanced app settings,
# App execution aliases, then python.exe and python3.exe to Off

# Prefer the launcher in scripts, it does not depend on PATH order
py -3.13 -m pip install -r requirements.txt

# If the interpreter is genuinely missing, install it for the machine
winget install Python.Python.3.13 --scope machine

# Open a new terminal afterwards: PATH changes do not reach a running shell
python --version

How to diagnose Windows errors

Windows errors surface as numeric codes that mean little on their own, but the operating system keeps detailed logs that almost always contain the real cause. Two categories dominate developer machines: missing Visual C++ redistributables (a DLL-not-found error for a runtime the application assumed was present) and architecture or dependency mismatches (the 0xc000007b family, usually a 32-bit/64-bit mix).

If the quick fix above does not resolve it, work through these steps. They apply to this whole class of error, not just to this one message, which is usually what saves the time.

  1. Read Event Viewer under Windows Logs → Application and System, filtered to the time of the failure. The numeric code in the dialog maps to a detailed entry there.
  2. For MSI failures, install with verbose logging: msiexec /i package.msi /l*v install.log, then search the log for "Return value 3". The lines just above name the failing action.
  3. For missing DLLs, install the matching Visual C++ Redistributable and confirm the architecture matches the application (x64 versus x86).
  4. Repair system corruption with sfc /scannow followed by DISM /Online /Cleanup-Image /RestoreHealth, in that order.
  5. For access-denied errors, check both NTFS permissions and whether the process needs elevation; UAC virtualisation can make writes appear to succeed while landing elsewhere.

Tools worth reaching for

  • Event Viewer
  • msiexec /l*v
  • sfc /scannow
  • DISM /RestoreHealth
  • Process Monitor (ProcMon)

Authoritative references

Primary documentation for this error, worth reading before applying any fix in production.

learn.microsoft.com docs.python.org

Related Windows errors

See all 20 Windows errors →

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Something missing or wrong?

This entry is maintained by hand. If the fix is out of date, incomplete, or you have a better one, email a correction and it will be reviewed.