VS Code IntelliSense Not Working - Complete Troubleshooting Guide

# VS Code IntelliSense Not Working

You're typing code and expecting the familiar dropdown of suggestions, but nothing appears. Or maybe you get suggestions, but they're wrong, outdated, or painfully slow. IntelliSense is the backbone of productive coding, and when it fails, you lose the efficiency gains that make VS Code worthwhile.

Understanding IntelliSense Architecture

IntelliSense in VS Code relies on language servers - separate processes that analyze your code and provide completions. When IntelliSense breaks, it's usually:

1. 1.The language server crashed or isn't running
2. 2.The language server can't find your project files
3. 3.Configuration is blocking or misdirecting IntelliSense
4. 4.TypeScript/JavaScript configuration is incomplete

Step 1: Check Language Server Status

Open the Output panel and select your language from the dropdown:

• For TypeScript/JavaScript: "TypeScript"
• For Python: "Python"
• For Go: "Go"

Look for errors like: `` [error] The TypeScript language server died unexpectedly [error] Cannot find module './some-module' [error] Project is not configured correctly

If the language server crashed, restart it:

TypeScript/JavaScript: Press Ctrl+Shift+P → "TypeScript: Restart TS Server"

Python: Press Ctrl+Shift+P → "Python: Restart Language Server"

General: Reload VS Code: Ctrl+Shift+P → "Developer: Reload Window"

Step 2: Verify TypeScript Configuration

For JavaScript and TypeScript projects, a proper tsconfig.json is essential:

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}

Common issues:

• Missing include array: TypeScript doesn't know which files to analyze
• Wrong rootDir: Paths won't resolve correctly
• Missing typeRoots or types: Third-party types aren't found

Create tsconfig.json if it doesn't exist: ``bash npx tsc --init

Step 3: Fix Missing Type Definitions

For JavaScript projects using libraries without built-in types:

# Install type definitions
npm install --save-dev @types/node @types/express @types/react

For libraries without type definitions: ``bash # Create a declarations file touch declarations.d.ts

Add minimal type declarations: ``typescript // declarations.d.ts declare module 'untyped-library' { export function someFunction(input: string): any; }

Step 4: Check JavaScript Configuration

If you're not using TypeScript but still want IntelliSense in JavaScript:

Create jsconfig.json: ``json { "compilerOptions": { "baseUrl": ".", "paths": { "@/*": ["src/*"] }, "target": "ES6", "module": "commonjs", "checkJs": true }, "include": ["src/**/*"], "exclude": ["node_modules"] }

This enables path mapping and better IntelliSense for JS projects.

Step 5: Fix Python IntelliSense Issues

Python IntelliSense requires proper interpreter selection:

1. 1.Select interpreter:
2. 2.Press Ctrl+Shift+P
3. 3."Python: Select Interpreter"
4. 4.Choose the correct virtual environment

Install language server components: ``bash pip install pylance # or for Jedi pip install jedi

Check Pylance settings: ``json { "python.languageServer": "Pylance", "python.analysis.typeCheckingMode": "basic", "python.analysis.autoImportCompletions": true }

Regenerate Python analysis cache: ``bash # Delete cached analysis rm -rf .vscode/settings.json # Reload window

Step 6: Resolve File Watcher Limits

If IntelliSense is slow or doesn't update when files change, you might be hitting file watcher limits.

Linux: ```bash # Check current limit cat /proc/sys/fs/inotify/max_user_watches

# Increase limit permanently echo "fs.inotify.max_user_watches=524288" | sudo tee -a /etc/sysctl.conf sudo sysctl -p ```

macOS: File watching usually works, but for large projects: ``json { "files.watcherExclude": { "**/.git/**": true, "**/node_modules/**": true, "**/dist/**": true, "**/build/**": true } }

Step 7: Check for Conflicting Extensions

Multiple language extensions can conflict:

code --list-extensions

Look for: - Multiple Python extensions (Python, Pylance, Python Indent, etc.) - Multiple JavaScript/TypeScript extensions - Multiple formatters for the same language

Disable potential conflicts and test: ``bash code --disable-extension <extension-id>

Step 8: Fix Path Mapping Issues

If you use path aliases (@/components/Button), IntelliSense needs to know about them:

TypeScript (tsconfig.json): ``json { "compilerOptions": { "baseUrl": ".", "paths": { "@/*": ["src/*"], "@components/*": ["src/components/*"] } } }

JavaScript (jsconfig.json): ``json { "compilerOptions": { "baseUrl": ".", "paths": { "@/*": ["src/*"] } } }

Webpack aliases must match: ``javascript // webpack.config.js module.exports = { resolve: { alias: { '@': path.resolve(__dirname, 'src') } } };

Step 9: Clear Caches and Rebuild

Sometimes cached data becomes corrupted:

Delete TypeScript cache: ``bash rm -rf node_modules/.cache rm -rf .tsbuildinfo

Reinstall dependencies: ``bash rm -rf node_modules npm install

Clear VS Code cached data: Press Ctrl+Shift+P → "Developer: Clear Cache"

Rebuild IntelliSense index: Press Ctrl+Shift+P → "TypeScript: Restart TS Server"

Verification

Test IntelliSense is working:

1. 1.Type console. in a JavaScript file
2. 2.You should see log, error, warn, etc.
3. 3.Select one - it should show the function signature
4. 4.For Python, type import os then os. - you should see path functions

Common Error Patterns

IntelliSense problems usually stem from configuration issues. Start with language server status, then verify your TypeScript or JavaScript configuration, and finally check for missing type definitions.