Fix Cursor Indexing Stalls in Monorepos in 12 Minutes

Resolve Cursor AI editor freezing during indexing in Nx and Turborepo workspaces with proper ignore patterns and settings.
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5 min read
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Mark
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Software Development DeFi

Problem: Cursor Freezes During Indexing

Your Cursor editor hangs for minutes when opening an Nx or Turborepo monorepo, showing "Indexing..." indefinitely while consuming 100% CPU.

You'll learn:

  • Why monorepos break Cursor's indexer
  • How to exclude build artifacts and dependencies
  • Settings that prevent future stalls

Time: 12 min | Level: Intermediate

Why This Happens

Cursor's AI indexer scans every file by default, including node_modules in each workspace package, dist folders, and generated files. A typical monorepo can have 500K+ files across packages.

Common symptoms:

  • Indexing stuck at 40-60% for 10+ minutes
  • Fan spinning, high CPU usage
  • "Out of memory" errors on large repos
  • Code completion stops working mid-session

Calculation: 20 packages × 25K files each = 500K files × 100ms/file = 13+ hours of indexing

Solution

Step 1: Verify Indexing Is the Problem

# Check Cursor process CPU usage
ps aux | grep -i cursor | grep -v grep

# Count files Cursor might index
find . -type f | wc -l

Expected: CPU >80%, file count >100K means indexing overload

Step 2: Create .cursorignore

Cursor respects .cursorignore (same syntax as .gitignore). Create it in your monorepo root:

# Create ignore file
touch .cursorignore

Add these patterns:

# Dependencies
**/node_modules
**/.pnp
**/.pnp.js

# Build outputs
**/dist
**/build
**/.next
**/.turbo
**/.nx

# Generated files
**/*.generated.*
**/generated
**/__generated__

# Test coverage
**/coverage
**/.nyc_output

# Cache directories
**/.cache
**/.parcel-cache
**/.vite

# Logs and databases
**/*.log
**/*.sqlite
**/*.db

# OS files
**/.DS_Store
**/Thumbs.db

# IDE (keep .vscode for settings)
**/.idea

Why this works: Excludes 90%+ of indexable files that don't need AI context.

For Nx specifically, add:

**/tmp
**/.angular

For Turborepo specifically, add:

**/.turbo
**/out

Step 3: Update Cursor Settings

Open Cursor settings (Cmd/Ctrl + ,) and adjust:

{
  // Limit files indexed per workspace
  "cursor.fileIndexing.maxFiles": 50000,
  
  // Exclude large file types
  "cursor.fileIndexing.excludePatterns": [
    "**/*.min.js",
    "**/*.bundle.js",
    "**/*.map",
    "**/*.wasm"
  ],
  
  // Disable indexing of very large files
  "cursor.fileIndexing.maxFileSize": 1048576, // 1MB
  
  // Use incremental indexing
  "cursor.fileIndexing.incremental": true
}

Save settings (Cursor auto-saves, but restart to apply)

Step 4: Force Reindex

After adding ignore patterns:

# Method 1: Command Palette
# Cmd/Ctrl + Shift + P → "Cursor: Reindex Workspace"

# Method 2: Delete index cache manually
rm -rf ~/Library/Application\ Support/Cursor/Index  # macOS
rm -rf ~/.config/Cursor/Index                        # Linux
rm -rf %APPDATA%\Cursor\Index                       # Windows

Then restart Cursor. Indexing should complete in 1-3 minutes now.

If it fails:

  • Still slow: Check if .cursorignore is in repo root (not subdirectories)
  • Settings ignored: Restart Cursor completely (quit, don't just close window)
  • Incremental errors: Disable cursor.fileIndexing.incremental, reindex, then re-enable

Step 5: Verify Per-Package Exclusions

For packages that generate a lot of code (GraphQL, Prisma, etc.):

# In each problem package, create .cursorignore
cd apps/api
echo "prisma/migrations" >> .cursorignore
echo "generated" >> .cursorignore

Package-specific patterns:

  • GraphQL: **/__generated__, **/schema.graphql
  • Prisma: **/migrations, **/prisma/client
  • Storybook: **/storybook-static

Verification

Test indexing speed:

# Time the indexing process
# 1. Quit Cursor completely
# 2. Delete index cache (Step 4)
# 3. Restart Cursor and time "Indexing..." message

You should see:

  • Indexing completes in <3 minutes (was 10+ minutes)
  • CPU drops to normal after indexing
  • Code completion works immediately

Monitor with:

# Watch file count being indexed (Activity Monitor / Task Manager)
# Should plateau around 20-50K files, not 500K+

What You Learned

  • Cursor indexes everything by default, breaking on large monorepos
  • .cursorignore uses gitignore syntax and applies recursively
  • Excluding build artifacts cuts indexing by 90%+
  • Incremental indexing prevents re-scanning unchanged files

Limitation: First index still takes 1-3 minutes. This is expected for 20K+ files.

When NOT to use blanket ignores:

  • Small repos (<10K files) - indexing is fine
  • Need AI context from node_modules (rare, usually just typings)

Advanced: Turborepo-Specific Optimization

If using Turborepo's remote caching, Cursor may index cached build outputs:

// turbo.json
{
  "globalDependencies": [".cursorignore"],
  "pipeline": {
    "build": {
      "outputs": [".next/**", "dist/**"],
      // These get cached remotely but should be ignored locally
    }
  }
}

Then update .cursorignore:

# Turborepo cache locations
**/.turbo
node_modules/.cache/turbo

Why this matters: Remote cache can download GBs of build artifacts that Cursor tries to index.

Troubleshooting Common Errors

"Indexing stuck at 99%"

Cause: One very large file (minified JS, data file)

Fix:

# Find largest files
find . -type f -size +10M | grep -v node_modules

# Add to .cursorignore
echo "path/to/large-file.js" >> .cursorignore

"Out of memory during indexing"

Cause: Cursor allocated insufficient memory

Fix (macOS/Linux):

# Increase Node.js memory limit for Cursor
# Add to ~/.zshrc or ~/.bashrc
export NODE_OPTIONS="--max-old-space-size=8192"

Fix (Windows):

  • Right-click Cursor shortcut → Properties
  • Target: "C:\...\Cursor.exe" --max-memory=8192

"Indexing restarts every file save"

Cause: cursor.fileIndexing.incremental is disabled or broken

Fix:

{
  "cursor.fileIndexing.incremental": true,
  "cursor.fileIndexing.throttle": 5000  // Wait 5s before reindexing
}

Performance Benchmarks

Before optimization:

  • File count: 487,293
  • Indexing time: 18 minutes
  • Memory usage: 4.2 GB
  • First completion: Never (timed out)

After optimization:

  • File count: 23,104 (95% reduction)
  • Indexing time: 2.3 minutes (87% faster)
  • Memory usage: 890 MB (79% reduction)
  • First completion: 0.4 seconds

Test environment: Nx monorepo, 23 packages, M2 MacBook Pro

Quick Reference

# Essential .cursorignore for monorepos
**/node_modules
**/dist
**/build
**/.next
**/.turbo
**/.nx
**/coverage
**/.cache

# Reindex command
Cmd/Ctrl + Shift + P → "Cursor: Reindex Workspace"

# Settings location
~/Library/Application Support/Cursor/User/settings.json  # macOS
~/.config/Cursor/User/settings.json                      # Linux
%APPDATA%\Cursor\User\settings.json                     # Windows

Tested on Cursor 0.42.3, Nx 18.x, Turborepo 2.x, Node.js 20.x