Install Claude Code on Windows and fix every error

Before you start

• Windows 10 version 1809 or newer (or Windows Server 2019+), 64-bit, with at least 4 GB of RAM.
• A paid Claude plan: Pro, Max, Team, Enterprise, or a Console account. The free plan can install Claude Code but can't use it.
• No admin rights, Node.js or WSL needed.

Open the Start menu, type PowerShell, and open Windows PowerShell. Not Command Prompt, and not the entry ending in (x86). You're in the right place when the prompt starts with PS. Paste this and press Enter:

irm https://claude.ai/install.ps1 | iex

Other ways to install

curl -fsSL https://claude.ai/install.cmd -o install.cmd && install.cmd && del install.cmd

Close the window you installed from and open a fresh one. A terminal keeps the PATH it had when it opened, so the old window may not find claude even after a good install. Then run:

claude --version

• A version number followed by (Claude Code): it worked. Go to step 3.
• An error: find it in the error finder.
• Something feels off but there's no error: run claude doctor. It only reads, changes nothing, and lists warnings with suggested fixes.

Skip this unless your projects use shell scripts written for Mac or Linux. Without Git for Windows, Claude Code runs commands through PowerShell. With it, Claude Code also gets Git Bash.

Install Git from git-scm.com and pick Add to PATH during setup. If Git lives somewhere other than C:\Program Files\Git, set its location in %USERPROFILE%\.claude\settings.json:

{
  "env": {
    "CLAUDE_CODE_GIT_BASH_PATH": "C:\\Program Files\\Git\\bin\\bash.exe"
  }
}

Open a terminal in a project folder and run claude. Your browser opens to sign in. If it doesn't, press c to copy the sign-in link and paste it into your browser. If you've set an ANTHROPIC_API_KEY environment variable, Claude Code asks you to approve that key instead.

That's it: Claude Code is installed. Everything below is for when a step goes wrong.

Error finder

Match the first line of what your terminal printed.

'claude' is not recognized

Why: Windows only runs programs from folders on your PATH, and Claude Code lives in %USERPROFILE%\.local\bin. That folder isn't on the PATH yet, or this window opened before it was added.

Fix: work down this list and stop when claude --version works.

1. Open a new terminal. This fixes it most of the time.
2. Check that the folder is on your PATH. No output means it's missing:
   PowerShell Copy

   $env:PATH -split ';' | Select-String '\.local\\bin'

3. Add it to your user PATH, then open a new terminal:
   PowerShell Copy

   $currentPath = [Environment]::GetEnvironmentVariable('PATH', 'User')
   [Environment]::SetEnvironmentVariable('PATH', "$currentPath;$env:USERPROFILE\.local\bin", 'User')

4. Only have the VS Code extension? It keeps a private copy of Claude Code and adds no claude command. Run the installer from step 1.

The claude command works in PowerShell, but not in the VS Code or Cursor terminal

Why: an editor's built-in terminal gets its settings, including the PATH, from the editor, which reads them once, when it starts. If VS Code or Cursor was already open when you installed Claude Code, even a brand-new terminal tab inside it still has the old PATH.

Fix: close the editor completely, every window, then open it again and open a new terminal. Still not found? Check that you installed the terminal version from step 1: the VS Code extension on its own doesn't add a claude command.

'irm' is not recognized

Why: irm only exists in PowerShell.

Fix: open Windows PowerShell and run the step 1 command, or stay in Command Prompt and use the Command Prompt installer.

The token '&&' is not a valid statement separator

Why: Windows PowerShell, the version built into Windows, doesn't understand &&. That's Command Prompt syntax.

Fix: in PowerShell, use the PowerShell command:

irm https://claude.ai/install.ps1 | iex

A parameter cannot be found that matches parameter name 'fsSL'

Why: in Windows PowerShell, curl is really Invoke-WebRequest, which doesn't know the Mac and Linux flags. If you see 'bash' is not recognized instead, it's the same mistake.

Fix: use the step 1 command. The install.sh installer is for Mac, Linux and WSL only.

The script's text prints, and nothing installs

Why: irm https://claude.ai/install.ps1 downloads the installer and prints it. The | iex at the end is the part that runs it.

Fix: paste the whole line from step 1. In Command Prompt, the same happens if -o install.cmd is missing.

running scripts is disabled on this system

npm : File C:\Program Files\nodejs\npm.ps1 cannot be loaded because running
scripts is disabled on this system.

Why: this only happens with an npm install. PowerShell's execution policy blocks the .ps1 launchers npm creates, including claude.ps1.

Fix: pick one.

• Easiest: skip npm and use the step 1 installer. It installs a program, not a script.
• Keep npm: allow scripts for your account, then retry:
  PowerShell Copy

  Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

• Leave the policy alone: type claude.cmd instead of claude.

The process cannot access the file

Failed to download binary: The process cannot access the file ... because it is
being used by another process

Why: another installer window is still running, or antivirus is scanning the half-finished download.

Fix: close other PowerShell windows, wait a minute for the scan, then clear the download folder and install again:

Remove-Item -Recurse -Force "$env:USERPROFILE\.claude\downloads"
irm https://claude.ai/install.ps1 | iex

Claude Code does not support 32-bit Windows

Why: almost always, you opened Windows PowerShell (x86), which runs as a 32-bit program even on 64-bit Windows.

Fix: close it, open plain Windows PowerShell, and install again.

Check: not sure? Run this in the window that failed. True means your Windows is fine and only the window was wrong. False means the machine really is 32-bit, and Claude Code won't run on it.

[Environment]::Is64BitOperatingSystem

Claude Code on Windows requires either Git for Windows (for bash) or PowerShell

Why: Claude Code found neither shell.

Fix:

• PowerShell missing from PATH: add C:\Windows\System32\WindowsPowerShell\v1.0\ to your PATH, or install PowerShell 7.
• Git installed but not found: run where.exe git, then set CLAUDE_CODE_GIT_BASH_PATH to that install's bin\bash.exe, as in step 3.
• Right path, still failing on a work laptop: security software such as AppLocker may be blocking it. Ask IT to allow claude.exe and the cmd.exe and bash.exe processes it starts.

Typing claude opens the Desktop app

Why: an older Claude Desktop app registered its own Claude.exe in a folder Windows checks first.

Fix: update the Desktop app to the latest version.

unable to get local issuer certificate, 403, or TLS errors

Why: the download didn't arrive intact. Company laptops, school networks and some VPNs inspect or block it. The one exception is App unavailable in region, which means Claude Code isn't offered in your country.

Fix: try once from another connection, such as a phone hotspot. If it works there, the network is the problem, and Anthropic documents how your IT team can configure a corporate certificate.

cannot execute binary file: Exec format error

Why: you're in WSL 1 and hitting a known problem with how it loads Claude Code (issue #38788).

Fix: move your distribution to WSL 2. In PowerShell, list your distributions, then convert yours by name:

wsl -l -v
wsl --set-version Ubuntu 2

Replace Ubuntu with the name from the list, then run claude again inside WSL. If you must stay on WSL 1, Anthropic documents a workaround.

OAuth error or 403 Forbidden after signing in

Why: usually the account has no Claude Code access, which is the case on the free plan, or the sign-in got stuck.

Fix: confirm you're signing in with the account that has the paid plan. Then reset your sign-in: type /logout inside Claude Code, close it, run claude, and sign in again. For rarer cases, see Anthropic's login troubleshooting.

Native Windows or WSL?

Stay on native Windows unless one of these is true:

• Your projects already live in WSL. Keep Claude Code next to the code.
• You want sandboxed commands. Sandboxing works on WSL 2, not on native Windows.
• Your toolchain is Linux-only.

If you use WSL, keep projects under /home/, not /mnt/c/, where search is slow and can miss files.

Keeping it updated

The PowerShell and Command Prompt installers update Claude Code in the background; the new version takes over the next time you run claude. To update now, run claude update.

WinGet installs don't update on their own. Either upgrade by hand, with every Claude Code window closed so Windows doesn't lock the file:

winget upgrade Anthropic.ClaudeCode

Or set the environment variable CLAUDE_CODE_PACKAGE_MANAGER_AUTO_UPDATE to 1, and Claude Code runs that upgrade for you in the background, then asks you to restart.

Starting clean

If nothing worked, reinstall. First check for a second copy, such as an old npm install next to a new one:

where.exe claude

Remove whichever you have, then run the step 1 installer again:

# PowerShell or Command Prompt installer
Remove-Item -Path "$env:USERPROFILE\.local\bin\claude.exe" -Force
Remove-Item -Path "$env:USERPROFILE\.local\share\claude" -Recurse -Force

# WinGet
winget uninstall Anthropic.ClaudeCode

# npm
npm uninstall -g @anthropic-ai/claude-code

Your settings, MCP servers and session history stay in %USERPROFILE%\.claude. Leave that folder alone to keep them.

Next steps

• Your first session: Anthropic's quickstart walks through a first task in a real project.
• Make it follow your rules: set up hooks so Claude Code formats code and blocks risky commands on its own.

Checked against Anthropic's setup and install troubleshooting documentation in September 2026. Screenshots captured on Windows 10 with Windows PowerShell 5.1; other error messages are quoted from those docs. If a fix here has stopped working, tell us and it gets fixed.