AI AI Tools Guidebook
Troubleshooting

Cursor Tab Suggestions Stopped Appearing

Grey inline completions vanished — Tab toggled off, sign-in expired, Copilot stealing the key, or current file is too large / unsupported.

Published: Author: AI Productivity Guide Team 🌐 查看中文版本

The grey inline completion that used to follow your cursor just stopped. Pressing Tab inserts a regular indent. Sometimes it only fails in certain files. Cursor Tab is a low-latency in-house model that needs the client toggle on, a valid sign-in, exclusive Tab keybinding, and a supported file type. Any of those broken → suggestions silently disappear.

Fix by ruling out in order: setting → sign-in → extension conflict → file itself → network.

Common causes

1. Tab toggle is off

Cursor → Settings → Features → “Tab” master toggle, or Settings → Cursor Tab → “Enable Cursor Tab.” You or .vscode/settings.json may have disabled it.

How to judge: Cmd+Shift+P → “Preferences: Open Settings (UI)” → search “cursor tab” → check the toggle.

2. Sign-in expired or quota exhausted

Tab goes through Cursor’s backend; expired login / Pro quota gone / Hobby free Tab exhausted → server refuses, no UI alert.

How to judge: bottom-left avatar shows your account? Settings → Usage — Tab quota at 0?

3. Another completion extension grabbed Tab

GitHub Copilot, Tabnine, IntelliCode, Codeium installed simultaneously — they fight over Tab keybinding. Last registered wins.

How to judge: extensions panel — any Copilot etc. still installed? Cmd+K Cmd+S → search “tab” — see who’s bound.

4. File type / size unsupported

Cursor Tab disables itself on binary files, files > ~1MB, long pure-markdown documents, etc.

How to judge: open a fresh 50-line .ts test file; Tab should fire. If it does, the original file is the issue.

5. Language disabled

Settings → Cursor Tab → “Disabled languages” lets you ban languages. Repo .vscode/settings.json may add "cursor.cpp.disabledLanguages": ["markdown", "plaintext"].

How to judge:

grep -r "disabledLanguages" .vscode/ ~/Library/Application\ Support/Cursor/User/settings.json

6. Network / firewall blocks Cursor Tab backend

Tab backend must respond in < 300ms or no suggestion appears. Corporate VPN / firewall / restricted region routes often time out silently.

How to judge: try a different network (phone hotspot); View → Output → Cursor for “tab request timeout.”

Before you start

  • Distinguish “no Tab anywhere” vs “no Tab in this one file” — different fixes.
  • Commit .vscode/settings.json before tweaking.
  • Note Cursor version, current file path + extension + size.

Info to collect

  • Cursor version, plan (Hobby / Pro / Business).
  • Screenshot of Settings → Usage (Tab quota remaining).
  • Extensions list (Copilot etc. still installed?).
  • Current file path, size, language.
  • Last 50 lines of View → Output → Cursor.

Shortest fix path

Ordered by hit rate.

Step 1: Confirm Tab is on

Cmd+Shift+P → “Cursor: Toggle Cursor Tab.” Or:

Settings → Features → Cursor Tab → ✓ Enable Cursor Tab
Settings → Editor → Inline Suggest → ✓ Enabled

Step 2: Check sign-in + quota

Bottom-left avatar — signed in?
Settings → Usage — Tab requests remaining?

Hobby out → wait for next month or upgrade. Pro Tab is unlimited but needs valid sign-in.

Step 3: Disable conflicting extensions

Extensions panel → find GitHub Copilot / Tabnine / Codeium → Disable (Workspace) or Uninstall

If you don’t want to uninstall Copilot, at least disable inline:

// settings.json
{
  "github.copilot.enable": { "*": false }
}

Step 4: Test current file vs a fresh file

Create test.ts:

function add(a: number, b

Park cursor after b, wait 1s. Tab fires → original file’s the problem (size / language). Doesn’t fire → global issue (settings / sign-in / network).

Step 5: Relax disabled languages

// settings.json — clear these
{
  "cursor.cpp.disabledLanguages": []
}

Step 6: Switch network or configure proxy

Corporate network blocks cursor backend:

Settings → search "proxy" → set HTTP proxy URL

Or temporarily switch to phone hotspot. If Tab works on hotspot but not at the office, ask IT to allowlist cursor.sh / cursor.com.

How to verify the fix

  • Type in multiple file types (.ts / .py / .md) — grey completion appears each time.
  • Restart Cursor and reproduce — not transient.
  • Sign into the same account on another machine — Tab works there too.

If it still fails

  • Reduce repro: fresh file + one-line function.
  • Roll back the most recent Cursor upgrade or settings.json change.
  • Search forum.cursor.com for “tab not suggesting”; include version + screenshots.
  • Grab View → Output → Cursor logs and post to Bug Reports.

Prevention

  • One completion tool per IDE; don’t run Copilot + Cursor side-by-side.
  • Monthly look at Settings → Usage; Hobby users plan around month-end.
  • Allowlist *.cursor.sh and *.cursor.com in corporate proxy.
  • When editing .vscode/settings.json, careful with disabledLanguages — easy to nuke a whole language.
  • Before high-stakes work, verify Tab still fires after any network switch.

Tags: #Troubleshooting #Cursor #Debug

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