PowerShell: 'File ... cannot be loaded because running scripts is disabled on this system' (execution policy, about_Execution_Policies). How do I allow my scripts without weakening security?

Cause: PowerShell's execution policy on Windows controls whether script files (.ps1) run. The default on Windows client editions is Restricted, which allows interactive commands but no scripts, so running a script, an npm/yarn shim (npm.ps1), or a virtualenv's Activate.ps1 fails with this message. Execution policy is a safety feature to prevent accidental script execution, not a security boundary; it can be set per scope (process, current user, local machine) and by Group Policy. Fix (narrowest first): 1. See what applies: Get-ExecutionPolicy -List shows each scope and which one wins. 2. For your own user, allow local scripts while still requiring signatures for downloaded ones: Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser. This needs no admin rights and is what Microsoft documents for most developer machines. 3. For a single session only (e.g. a build step): Set-ExecutionPolicy -ExecutionPolicy Bypass -Scope Process, or start powershell -ExecutionPolicy Bypass -File script.ps1. It ends when the window closes. 4. Scripts downloaded from the internet carry a 'mark of the web'; under RemoteSigned they're blocked until you review them and run Unblock-File .\script.ps1. 5. If Group Policy sets the policy (MachinePolicy/UserPolicy scopes), you can't override it locally; ask your administrator, or use cmd shims instead (npm.cmd instead of npm.ps1). 6. Avoid Unrestricted or Bypass at the LocalMachine scope just to make one tool work. Verify: Get-ExecutionPolicy -List shows RemoteSigned for CurrentUser (or your chosen scope), and the script runs. Sources: https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_execution_policies https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.security/set-executionpolicy