Cursor Common Errors

Diagnostic and resolution guide for the most frequent Cursor IDE issues. Organized by error category with specific symptoms, causes, and fixes.

Authentication Errors

"Sign-in failed" / OAuth Loop

Symptoms: Browser opens for auth, redirects back, Cursor still shows "Sign In".

Fix:

1. Clear browser cookies for cursor.com and auth.cursor.com
2. Try incognito/private window for the OAuth flow
3. Check if browser is blocking popups from cursor.com
4. Try a different auth method (GitHub vs Google vs email)

"License not found" / "No active subscription"

Symptoms: Signed in but AI features are disabled.

Fix:

1. Verify subscription at cursor.com/settings
2. Confirm the email address matches your Cursor account
3. Sign out (Cmd+Shift+P > Sign Out) then sign back in
4. If on a team plan, ask admin to verify your seat is assigned

"Session expired"

Symptoms: Features stop working mid-session.

Fix: Cmd+Shift+P > Cursor: Sign Out > Sign back in. This refreshes the auth token.

AI Completion Errors

Tab Suggestions Not Appearing

Symptoms: No ghost text while typing.

Causes and fixes:

"Request failed" / "Model unavailable"

Symptoms: Chat or Composer returns an error instead of a response.

Fix:

1. Check status.cursor.com for outages
2. Switch to a different model (model dropdown in Chat/Composer)
3. If using BYOK, verify API key is valid and has credits
4. Try a shorter prompt (may have hit context limit)

Poor Quality Suggestions

Symptoms: AI generates irrelevant, outdated, or incorrect code.

Fix:

1. Add context: use @Files to reference relevant code
2. Add project rules: create .cursor/rules/*.mdc with your patterns
3. Switch model: try Claude Opus or GPT-5 for complex tasks
4. Start a new chat: long conversations degrade quality
5. Be more specific: "Add Zod validation to the user endpoint" beats "fix validation"

Indexing Errors

"Indexing stuck" / Never Completes

Symptoms: Status bar shows "Indexing..." indefinitely.

Fix:

1. Check .cursorignore -- exclude node_modules/, dist/, large data files
2. Cmd+Shift+P > Cursor: Resync Index
3. Close and reopen the workspace
4. Delete index cache:

   macOS: rm -rf ~/Library/Application\ Support/Cursor/Cache/
   Linux: rm -rf ~/.config/Cursor/Cache/

5. Restart Cursor

"@Codebase returns no results"

Symptoms: Codebase search finds nothing, even for known code.

Fix:

1. Wait for indexing to complete (check status bar)
2. Verify the file is not in .cursorignore or .gitignore
3. Resync the index
4. Check network connectivity (embeddings require API access)

Performance Errors

Cursor is Slow / Freezing

Symptoms: Editor lags, typing delays, UI freezes.

Diagnosis and fixes:

Step 1: Open Process Explorer
  Cmd+Shift+P > "Developer: Open Process Explorer"
  Identify which process uses most CPU/memory

Step 2: Extension audit
  Disable extensions one-by-one to find the culprit
  Common offenders: GitLens (large repos), Prettier (on save), ESLint

Step 3: Reduce indexed scope
  Add large directories to .cursorignore

Step 4: Clear chat history
  Long chat sessions consume memory. Start new chats frequently.

Step 5: Increase memory limit
  settings.json: "files.maxMemoryForLargeFilesMB": 4096

High CPU After Startup

Symptoms: CPU spikes for minutes after opening a project.

Cause: Initial indexing + extension loading.

Fix: Wait for indexing to complete. Add aggressive .cursorignore patterns. Close unused workspace folders.

Extension Errors

Extension Not Found / Install Failed

Symptoms: Extension from VS Code Marketplace not available.

Cause: Cursor uses Open VSX Registry, not Microsoft's marketplace.

Fix:

1. Search the extension on open-vsx.org
2. If not on Open VSX, download .vsix from VS Code Marketplace website
3. Cmd+Shift+P > Extensions: Install from VSIX...

Extension Conflicts with AI Features

Common conflicts:

Network Errors

"Connection refused" / "Timeout"

Symptoms: AI features fail but editor works fine.

Fix:

1. Check internet connectivity
2. Check if corporate firewall/proxy blocks *.cursor.com
3. Required domains to allowlist:

   api.cursor.com
   api2.cursor.com
   auth.cursor.com
   *.turbopuffer.com (for indexing)

4. If using VPN, try disconnecting temporarily

Crash Recovery

Cursor Won't Start

# Start with extensions disabled
cursor --disable-extensions

# Start with GPU disabled (Linux/Windows)
cursor --disable-gpu

# Reset to defaults (nuclear option -- backs up settings first)
# macOS:
cp -r ~/Library/Application\ Support/Cursor ~/cursor-backup
rm -rf ~/Library/Application\ Support/Cursor/Cache
rm -rf ~/Library/Application\ Support/Cursor/CachedData

Recovering Unsaved Work

Cursor auto-saves by default. Check:

• File > Open Recent for recent files
• Hot exit preserves unsaved buffers between sessions
• Git reflog if changes were staged: git reflog

Enterprise Considerations

• Centralized troubleshooting: Document common errors and fixes in team wiki
• Proxy configuration: Enterprise proxy settings via settings.json:

  { "http.proxy": "http://proxy.corp.com:8080" }

• Support escalation: Business/Enterprise plans include priority support via Cursor dashboard
• Telemetry for diagnostics: Anonymous telemetry helps Cursor diagnose widespread issues (can be disabled)

Resources

• Cursor Status Page
• Cursor Community Forum
• Cursor GitHub Issues