Windows

---
name: Windows
slug: windows
version: 1.0.0
description: Windows-specific patterns, security practices, and operational traps that cause silent failures.
homepage: https://clawic.com/skills/windows
metadata:
  category: system
  skills:
  - windows
  - powershell
  - security
  - automation
  clawdbot:
    emoji: 🪟
    displayName: Windows
---

## Credential Management

- Never hardcode passwords in scripts — use Windows Credential Manager:
  ```powershell
  # Store
  cmdkey /generic:"MyService" /user:"admin" /pass:"secret"
  # Retrieve in script
  $cred = Get-StoredCredential -Target "MyService"
  ```
- For scripts, use `Get-Credential` and export securely:
  ```powershell
  $cred | Export-Clixml -Path "cred.xml"  # Encrypted to current user/machine
  $cred = Import-Clixml -Path "cred.xml"
  ```

## Silent Failures

- Windows Defender silently quarantines downloaded scripts/executables — check quarantine if script disappears
- Group Policy overrides local settings silently — `gpresult /r` to see what's actually applied
- Antivirus real-time scanning blocks file operations intermittently — add exclusions for build/automation folders
- PowerShell `-ErrorAction SilentlyContinue` hides problems — use `Stop` and handle explicitly

## Symbolic Links

- Creating symlinks requires admin OR SeCreateSymbolicLinkPrivilege — regular users fail silently
- Enable Developer Mode for symlinks without admin: Settings → For Developers → Developer Mode
- `mklink` is CMD-only, PowerShell uses `New-Item -ItemType SymbolicLink`

## Script Signing

- Unsigned scripts fail on restricted machines with confusing errors — sign for production:
  ```powershell
  $cert = Get-ChildItem Cert:\CurrentUser\My -CodeSigningCert
  Set-AuthenticodeSignature -FilePath script.ps1 -Certificate $cert
  ```
- AllSigned policy requires ALL scripts signed including profile.ps1

## Operational Safety

- Always `-WhatIf` first on destructive operations — `Remove-Item -Recurse -WhatIf`
- `Start-Transcript` for audit trail — forgotten until incident investigation
- NTFS permissions: `icacls` for CLI, but inheritance rules are non-obvious — test changes on copy first

## WinRM Remoting

- Enable correctly: `Enable-PSRemoting -Force` isn't enough on workgroups
- Workgroup machines need TrustedHosts: `Set-Item WSMan:\localhost\Client\TrustedHosts -Value "server1,server2"`
- HTTPS remoting needs certificate setup — HTTP sends credentials readable on network

## Event Logging

- Scripts should log to Windows Event Log for centralized monitoring:
  ```powershell
  New-EventLog -LogName Application -Source "MyScript" -ErrorAction SilentlyContinue
  Write-EventLog -LogName Application -Source "MyScript" -EventId 1000 -Message "Started"
  ```
- Custom event sources require admin to create — create during install, not runtime

## File Locking

- Windows locks files aggressively — test file access before operations:
  ```powershell
  try { [IO.File]::OpenWrite($path).Close(); $true } catch { $false }
  ```
- Scheduled tasks writing to same file as user → conflicts. Use unique temp files and atomic rename

## Temp File Hygiene

- `$env:TEMP` fills silently — scripts should cleanup with `try/finally`:
  ```powershell
  $tmp = New-TemporaryFile
  try { ... } finally { Remove-Item $tmp -Force }
  ```
- Orphaned temp files accumulate across reboots — unlike Linux /tmp

## Service Account Gotchas

- Services run in different user context — `$env:USERPROFILE` points to system profile, not user's
- Network access from SYSTEM account uses machine credentials — may fail where user succeeds
- Mapped drives don't exist for services — use UNC paths `\\server\share`