You hit Ctrl+C to copy. Nothing. Ctrl+V to paste. Nothing again. Your right-click menu still works — you can copy and paste with the mouse — but the muscle-memory shortcut you've used a million times suddenly does nothing. Or worse, it does something completely wrong, like opening a sidebar or closing a tab.
The good news: in nearly every case, your keyboard hardware is fine. Shortcut failures almost always come down to five fixable causes: a stuck modifier key, the wrong window having focus, an app intercepting the shortcut, an accessibility setting interfering, or a key remap you forgot you set up. Here's how to find which one — fast.
First: Test Ctrl, Shift, and Alt in KeyTest
The fastest diagnostic: open the KeyTest keyboard tester and press each modifier key one at a time — Ctrl, Shift, Alt, and the Windows key. Then look at the on-screen layout without touching anything.
- If a modifier shows as held without you pressing it: The key is physically stuck. Shortcuts will misfire because Windows always thinks Ctrl/Shift/Alt is down.
- If a modifier doesn't light up when you press it: The key is dead. No shortcut starting with that modifier will work. See our keys not working guide.
- If everything looks normal: The hardware is fine — the issue is software. Continue below.
Cause 1: The Wrong Window Has Focus
Easy to overlook, embarrassingly common: keyboard shortcuts only work in the window that currently has focus. If you clicked into a sidebar, dialog, or browser tab and forgot, the shortcut goes to the wrong place.
Quick fix: click directly into the area you're trying to copy from, then try the shortcut again. Especially common with browser-based apps where the document and the surrounding chrome are different focus targets.
Cause 2: Sticky Keys Is Active
Sticky Keys is a Windows accessibility feature that "latches" modifier keys after a single press, so you can do shortcuts one-handed. It activates by accident if you tap Shift five times in a row — which is very easy to do during a frustrating typing session.
When Sticky Keys is on, the timing of your shortcut changes completely. Tap Ctrl, then C — instead of holding Ctrl while pressing C — to make a shortcut work. If you're holding both at once, the behaviour can be unpredictable.
To turn it off:
- 1. Open Settings → Accessibility → Keyboard.
- 2. Toggle Sticky Keys off.
- 3. Also turn off Allow the shortcut key to start Sticky Keys so it doesn't reactivate.
On Mac: System Settings → Accessibility → Keyboard → Sticky Keys (toggle off).
Cause 3: The App Is Intercepting the Shortcut
Some applications — particularly remote desktop tools, virtual machines, terminal emulators, and certain games — capture keyboard input and reinterpret it before passing it to the underlying app. When this happens, Ctrl+C might be sent to the remote machine, not your local one.
- Remote Desktop / Citrix / RDP: Check the connection's keyboard pass-through settings. Some configurations send all shortcuts to the remote session, including local ones like Alt+Tab.
- Terminal apps (Windows Terminal, iTerm, etc.): Ctrl+C in a terminal sends an interrupt signal, not a copy command. Use Ctrl+Shift+C to copy in most modern terminals, or right-click.
- VS Code / IDEs: Check the keybindings panel — extensions can override default shortcuts.
- Web apps: Some web editors (Google Docs, Notion) handle shortcuts in JavaScript. A browser extension can sometimes block this.
Cause 4: A Remapping Tool Is Active
Tools like AutoHotkey, PowerToys Keyboard Manager, SharpKeys, or Karabiner-Elements (Mac) let you remap keys system-wide. If you set something up months ago and forgot, it can silently override common shortcuts.
Gaming keyboard software is the same: Razer Synapse, Logitech G Hub, Corsair iCUE, SteelSeries Engine all support per-profile remaps. A profile that auto-activates with a specific game can quietly remap keys whenever that game's executable is detected.
Quick check: open the manufacturer software, look at the active profile, and reset to default to test. If shortcuts work after the reset, you've found the culprit.
Cause 5: Corrupt Clipboard or Driver State
On Windows, Ctrl+C and Ctrl+V can fail in a particularly confusing way: the keys work, the shortcut fires, but nothing actually gets copied. The clipboard service has hung. Same symptom, different cause.
Test for it: try copying with right-click → Copy. If that also fails, the clipboard service is hung. Fix:
- 1. Press Ctrl+Shift+Esc to open Task Manager.
- 2. Find Windows Explorer, right-click → Restart.
- 3. If still broken, restart the computer entirely.
For shortcut keys themselves failing despite working modifiers: reinstall the keyboard driver via Device Manager (uninstall the keyboard, restart, Windows reinstalls automatically).
Mac-Specific: Cmd vs. Ctrl
If you're on a Mac and the shortcuts don't work, double-check you're pressing Cmd+C / Cmd+V, not Ctrl. macOS uses Cmd as the primary modifier for system shortcuts. Ctrl+C in a terminal sends an interrupt signal, like on Linux. This trips up Windows users on a Mac (and Mac users on a Windows keyboard) constantly.
5-cause diagnostic checklist