pathfix

Audit and repair your Windows PATH.

Your PATH rots. Uninstallers leave folders behind, installers add themselves twice, and two copies of the same tool end up fighting over which one runs. pathfix finds all of it, tells you which copy actually wins, and cleans up safely.

.\pathfix.ps1

Reports by default and changes nothing. -Fix writes, and every write is journaled to disk before it is applied so -Undo works even after a crash or a reboot.

If you have ever installed ffmpeg, Python or Node and then been told the command doesn't exist — or worse, watched the wrong version run — the cause is almost always PATH. pathfix answers both questions in one pass:

• Is the folder even there? Broken entries pile up silently after uninstalls.
• Which copy actually runs? If python.exe sits in three PATH folders, only the first one wins. pathfix names the winner and lists the ones it hides.

This is the part most PATH cleaners get wrong, and it is permanent.

Windows stores PATH as REG_EXPAND_SZ, so entries like %SystemRoot%\system32 stay as written and get expanded at use time. The obvious way to write it back from PowerShell is [Environment]::SetEnvironmentVariable, which expands every variable first and stores the result as plain text.

On the machine this was developed on, 5 of the 8 system PATH entries were variable references:

%SystemRoot%\system32
%SystemRoot%
%SystemRoot%\System32\Wbem
%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\
%SYSTEMROOT%\System32\OpenSSH\

A naive "cleanup" bakes all five into literal C:\WINDOWS\... paths. It usually still works — until the drive letter or the Windows folder differs, and then it does not. pathfix reads and writes the raw registry value and preserves the REG_EXPAND_SZ type, so what you wrote is what stays.

Verified directly:

BEFORE raw = %USERPROFILE%\Documents;...\good1;...\nope1;...\good1
AFTER  raw = %USERPROFILE%\Documents;...\good1

UNEXPANDED %USERPROFILE% SURVIVED : True
kind still ExpandString           : True

what a naive tool would have stored instead:
  C:\Users\hayyz\Documents      <- variable gone for good

• Dry run by default. Without -Fix, nothing is written.
• Journal first. The old PATH is written to %LOCALAPPDATA%\pathfix\ before the registry is touched. If the journal cannot be written, pathfix refuses to make the change.
• -Undo restores byte for byte, including the original registry value type.
• Undo refuses to clobber newer edits. If you changed PATH after pathfix ran, it stops and tells you instead of throwing your change away.
• User scope by default. Machine scope needs -Scope Machine and an elevated prompt; without elevation it says so and skips rather than failing.
• It only ever removes broken, duplicate and empty entries. Entries that need a judgement call — a file instead of a folder, a relative path, a variable that is not set — are reported and left alone.

# audit the User PATH
.\pathfix.ps1

# audit everything a new process actually sees
.\pathfix.ps1 -Scope Both

# clean it up
.\pathfix.ps1 -Fix

# changed your mind
.\pathfix.ps1 -Undo

Windows PowerShell 5.1 (ships with Windows 10/11) or PowerShell 7+. No dependencies, no installer, no network access. One file.

Want to remove broken folders but keep duplicates? -Fix -Prune Broken.

A genuine read-only audit of the development machine, -Scope Both:

  pathfix v1.0.0
  ----------------------------------------------------------------
  Machine       8 entries, 273 chars, ExpandString
  User          2 entries, 50 chars, ExpandString

  Problems
  ----------------------------------------------------------------
  [ ok ] no broken folders
  [ ok ] no duplicate entries
  [warn] 1 empty entry(s) - a stray semicolon
         an empty PATH entry means "the current folder", which is a mild security risk.
  [ ok ] PATH length 323 chars

  scanning for shadowed commands...
  scanned 9 folders in 0.6s
  [warn] 1 command(s) exist in more than one PATH folder
         notepad  (3 copies)
           runs -> C:\WINDOWS\system32\notepad.exe
           hidden  C:\WINDOWS\notepad.exe
           hidden  C:\Users\hayyz\AppData\Local\Microsoft\WindowsApps\notepad.exe
         the first folder in PATH order wins. This is why the wrong python runs.

  Summary
  ----------------------------------------------------------------
  healthy entries   9
  removable         1

  This was a dry run. Nothing was changed.
  Run with -Fix to remove the entries listed above.

That shadow result was cross-checked against Windows' own resolver:

where.exe notepad
  1. C:\Windows\System32\notepad.exe      <- pathfix called this the winner
  2. C:\Windows\notepad.exe
  3. C:\Users\hayyz\AppData\Local\Microsoft\WindowsApps\notepad.exe

Same winner, same order, same count.

A synthetic PATH was built with an exactly known set of defects, so every number could be checked rather than eyeballed:

A tool.exe was placed in three folders and a solo.exe in only one. pathfix reported exactly one shadowed command with three copies, named the first-in-PATH copy as the winner, ignored solo.exe, and ignored a notes.txt that was not executable.

The write path was tested against a scratch registry key so the real PATH was never involved:

• fix → undo produced a byte-identical value, with REG_EXPAND_SZ and every %VARIABLE% intact
• editing PATH after a fix and then running -Undo made pathfix stop and preserve the newer edit instead of restoring over it
• an empty PATH, a PATH with no problems, and Machine scope without elevation all behaved without a stack trace

Do I need to reboot? No. pathfix broadcasts the environment-change message Windows uses, so new terminals pick it up. Already-open terminals keep their old copy — that is how Windows works, not a pathfix limitation.

Is it safe to run -Fix on the Machine PATH? It is journaled and undoable like everything else, but it needs an elevated prompt and it affects every user on the machine. Read the dry run first.

Why is an empty entry a security risk? An empty PATH entry means "the current directory". Any folder you cd into can then supply an executable that runs ahead of the real one.

It says my PATH is over 2047 characters. The modern limit is much larger, but plenty of older installers and batch tooling still truncate at 2047 and fail in confusing ways. Removing duplicates and broken folders usually gets you back under.

Does it phone home? No network calls at all.

• obs-4k60-recorder — record 4K60 in OBS without dropped frames
• framecheck — diagnose a recording before you edit it
• clipmine — find the loud moments in a recording and cut them out
• gamemode — free up your machine before a session
• diskscout — find what is eating your disk
• dupefind — find duplicate files by content

MIT — see LICENSE.