How to fix npm ERR! code EPERM npm ERR! This operation requires administrator privileges in npm

This is the quickest temporary solution for global package installations:

1. Press Windows Key + X and select Terminal (Admin) or Command Prompt (Admin)
2. At the prompt, verify you see "Administrator:" in the title
3. Run your npm command:

npm install -g typescript
npm install -g @angular/cli

Note: This works for one-off global installs but isn't a permanent solution. You'll need admin access each time.

Reconfigure npm to use a user-writable directory instead of system-protected folders:

1. Open Command Prompt (regular user, no admin needed)
2. Check your current npm prefix:

npm config get prefix

3. Set it to your user's AppData folder:

npm config set prefix "%AppData%\npm"

4. Verify the change:

npm config get prefix

Should return: C:\Users\YourUsername\AppData\Roaming\npm

5. Add this directory to your system PATH if not already included
6. Close and reopen Command Prompt, then test:

npm install -g typescript

Running applications can lock files in your project, preventing npm from modifying them:

1. Close your IDE: Exit Visual Studio Code, Visual Studio, WebStorm, or any editor with your project open
2. Close file explorer: Close any Windows Explorer windows showing your project folder
3. Stop development server: Kill any running npm start, npm run dev, or npm test processes
4. Clear npm cache to ensure a fresh install:

npm cache clean --force

5. Delete existing node_modules and lock file:

rmdir node_modules /s /q
del package-lock.json

6. Retry installation:

npm install

If you're using npm workspaces or npm link, enabling Developer Mode allows non-admin users to create symlinks:

1. Press Windows Key + I to open Settings
2. Go to Privacy & Security → For developers
3. Toggle Developer Mode to ON
4. Click "Yes" in the popup confirmation
5. Windows will install required developer features (restart may be needed)
6. After enabling, retry your workspace or link command:

npm install
npm link ../local-package

Files marked as read-only can cause EPERM errors:

1. Navigate to your project folder in Windows Explorer
2. Right-click the node_modules folder → Properties
3. Check if "Read-only" is checked
- If yes, uncheck it
- Click "Apply", select "Apply changes to this folder, subfolders and files"
- Click OK
4. Also check your project root folder for read-only status
5. If that doesn't work, try changing ownership:
- Right-click node_modules → Properties → Security tab
- Click "Edit" → select your username → click "Full Control" → Apply
6. Retry npm install:

npm install