You glance at your screen and every letter you type is a capital. You check Caps Lock — it's off. The light is dark, the indicator shows nothing. And yet "HELLO" appears when you try to type "hello." This isn't just annoying — it makes you look like you're shouting in every email and message.
When Caps Lock isn't the culprit, the cause is almost always a stuck Shift key, an active accessibility feature, or a software setting that's silently toggling case for you. Here's how to identify which one it is, in the order you should check.
Step 1: Check Both Shift Keys With KeyTest
Before changing anything, open the KeyTest keyboard tester and look at both Shift keys on the on-screen layout — without touching them. If either one is highlighted (showing as "active" or "held"), you've found the problem instantly: a Shift key is physically stuck.
This single check tells you in five seconds whether the cause is hardware (stuck key) or software (everything else).
Step 2: Free a Stuck Shift Key
If KeyTest shows a Shift key permanently held, the key is mechanically stuck down. Common causes: debris underneath, sticky residue, or a damaged switch. Try in this order:
- Tap the Shift key firmly several times. Sometimes a key that's nearly stuck just needs a few full presses to free up.
- Compressed air. Tilt the keyboard, hold the can upright, and give 2–3 short bursts around the affected Shift key.
- Clean with isopropyl alcohol. A damp cotton swab around the keycap edges removes residue. Full method in our sticky key guide.
- For mechanical keyboards: Pop the keycap with a puller and inspect the switch. Visible damage means the switch needs replacement.
After cleaning, recheck KeyTest. If the Shift indicator is now off (and only lights up when you press the key), you've fixed it.
Step 3: Toggle Sticky Keys (Windows Accessibility)
Sticky Keys is a Windows feature that makes modifier keys "stick" after one press, so you can do shortcuts one-handed. If it's been activated by accident — pressing Shift five times in a row toggles it on — Shift can stay "stuck" in software even though no key is physically held.
- 1. Open Settings → Accessibility → Keyboard.
- 2. Toggle Sticky Keys off.
- 3. Also toggle off Allow the shortcut key to start Sticky Keys, so you don't accidentally re-enable it.
On Mac: System Settings → Accessibility → Keyboard → Sticky Keys. Toggle off.
Step 4: Check Caps Lock Indicator vs. State Mismatch
On rare occasions — usually after a wireless keyboard reconnects or a Bluetooth glitch — Caps Lock can be active in the OS even though the keyboard's indicator light says it's off. The states can desync.
Quick fix: press Caps Lock once. Then once more. The toggle resyncs the state with the indicator. If your keyboard has both an LED and an on-screen Caps Lock notification, watch both as you press it.
Step 5: Look for Auto-Capitalisation Settings
If only the first letter of words or sentences is being capitalised — not every letter — your keyboard is fine. The cause is autocorrect or app-level auto-capitalisation:
- Microsoft Word: File → Options → Proofing → AutoCorrect Options. Uncheck "Capitalize first letter of sentences."
- Google Docs: Tools → Preferences → uncheck "Automatically capitalize words."
- Browser/iOS/Android: Each platform has its own auto-cap toggle in keyboard settings.
Step 6: Check Keyboard Software Profiles
Razer Synapse, Logitech G Hub, Corsair iCUE, and similar tools can remap keys per-profile. If a profile has Shift remapped to "always held" or has been set to a custom layout, the OS sees Shift as constantly active. Open the relevant software, check the active profile, and reset to default if you're unsure.
Step 7: Reinstall the Keyboard Driver
As a final software fix on Windows: open Device Manager, expand Keyboards, right-click your keyboard, choose Uninstall device, then restart. Windows reinstalls the driver and clears any corrupted state.
All-caps diagnosis checklist