On laptops, F1 to F12 have two jobs: the standard function key and a hardware control such as volume or brightness printed on the same key. Which one you get by default is decided by an Fn lock, a firmware setting, or on a Mac a checkbox. When function keys “stop working”, the default has usually flipped. If the keys do nothing at all, a driver is missing.
Which problem do you have?
| Symptom | Cause | Fix |
|---|---|---|
| F-keys control brightness or volume, not their normal job | Multimedia mode is the default | Fn lock, BIOS setting, or Mac checkbox |
| F-keys do their normal job but the media controls never work | The opposite default | Hold Fn, or flip the same settings |
| F-keys do nothing in either mode | Missing hotkey driver | Driver section |
| Only some F-keys fail | Hardware | Hardware section |
Press the F-keys in the tester above with and without holding Fn. It shows whether the computer receives F5 or a media command.
Windows laptops
Toggle Fn lock
Most laptops have an Fn lock. Look for a padlock icon on the Esc key, the Caps Lock key, or one of the F-keys.
- Fn+Esc on Lenovo, HP, Asus, Acer and many others
- Fn+Caps Lock on some MSI and Razer models
- Fn+F11 or Fn+Insert occasionally
Press the combination once. Some laptops show a small on-screen indicator; on others an LED on the Fn or Esc key lights.
Change the default in BIOS or UEFI
If there is no Fn lock key, the default is set in firmware.
- Restart and press the setup key as the laptop boots: F2 (Dell, Asus, Acer, Lenovo), F10 (HP), F1 (some ThinkPads).
- Look for Function Key Behavior, Action Keys Mode, Hotkey Mode, or Fn Key Switch. It is usually under Configuration, Advanced or System Configuration.
- Set it to Function Key for standard F-keys, or Multimedia Key for hardware controls.
- Save and exit.
Use the manufacturer utility
Dell (Dell Optimizer or Power Manager), Lenovo (Vantage), HP (System Event Utility) and Asus (MyASUS or Armoury Crate) expose the same setting inside Windows. Check the keyboard or hotkeys section.
Mac
macOS defaults the top row to brightness, Mission Control, volume and so on. To make F1 to F12 the default:
- Open System Settings → Keyboard → Keyboard Shortcuts → Function Keys.
- Turn on Use F1, F2, etc. keys as standard function keys.
With that on, hold the Fn or Globe key to reach the hardware controls. On a Touch Bar Mac, the same setting decides whether the Touch Bar shows F-keys, and you can set it per app under Shortcuts → Function Keys.
Missing drivers
If the F-keys produce nothing in either mode, or the media functions never work, the hotkey driver that translates the Fn combinations is missing. Windows Update does not always supply it.
- Go to the manufacturer’s support site and enter your model.
- Download the keyboard hotkey, system interface, quick launch or chipset driver, which varies by brand: HP System Event Utility, Lenovo Hotkey Features, Dell Quickset or System Interface driver, Asus ATK Package.
- Install and restart.
For external keyboards with media keys, install the vendor software or check the keyboard’s mode switch.
Hardware
Function keys that fail in both modes and in the BIOS have a hardware fault. Because the whole row shares a line in the keyboard matrix, several F-keys dying together points to a trace or cable fault rather than debris. Some keys not working explains matrix faults, and How to remap keyboard keys shows how to move F5 or F11 onto a working key in the meantime.
Common F-key jobs, in case you are switching modes to reach one
| Key | Standard job |
|---|---|
| F1 | Help |
| F2 | Rename (Windows), edit cell (Excel) |
| F3 | Search |
| F4 | Alt+F4 closes a window; repeats last action in Excel |
| F5 | Refresh; Go To in Word and Excel |
| F7 | Spell check in Office |
| F11 | Full screen in browsers |
| F12 | Save As in Office; developer tools in browsers |
Fn lock combinations by brand
| Brand | Fn lock | Where the setting lives |
|---|---|---|
| Lenovo ThinkPad | Fn+Esc (FnLk printed on Esc) | Lenovo Vantage → Device → Input & Accessories |
| Lenovo IdeaPad, Yoga | Fn+Esc | BIOS → Configuration → Hotkey Mode |
| HP | Fn+Esc, or fn+Shift on some models | BIOS → System Configuration → Action Keys Mode |
| Dell | Fn+Esc | BIOS → POST Behavior → Fn Lock Options; also in Dell Power Manager |
| Asus | Fn+Esc | MyASUS → Customization → Keyboard Hotkeys; Armoury Crate on gaming models |
| Acer | Fn+F12 on some models, otherwise BIOS only | BIOS → Main → Function key behavior |
| MSI | Fn+Esc on recent models | MSI Center |
| Microsoft Surface | Dedicated Fn key with an LED; tap to toggle | No BIOS setting |
| Apple | No lock key | System Settings → Keyboard → Keyboard Shortcuts → Function Keys |
External keyboards
Full-size desktop keyboards have no Fn layer on F1 to F12 unless they are compact or gaming models. If F-keys on an external keyboard act as media keys, look for an Fn lock (often Fn+Esc or Fn+F12 for a few seconds) or a switch on the back. Mac users with a Windows keyboard should also check System Settings → Keyboard → Keyboard Shortcuts → Function Keys, which applies per keyboard.
Troubleshooting flow
- Test F-keys with and without Fn in the tester.
- Toggle Fn lock (Fn+Esc or the padlock key).
- Set Function Key Behavior in BIOS, or the Mac function keys checkbox.
- Install the manufacturer’s hotkey driver.
- Confirm in BIOS whether the keys work at all.
- Remap or repair.
Related
Frequently asked questions
Why does F5 change my screen brightness instead of refreshing? +
The laptop is in multimedia mode, where the function row controls hardware first. Hold Fn while pressing F5, or toggle Fn lock (usually Fn+Esc) to make F1 to F12 the default.
How do I make F-keys the default on my laptop? +
Toggle Fn lock with Fn+Esc if your Esc key has a padlock icon, or change the Function Key Behavior setting in BIOS or UEFI. On a Mac, turn on Use F1, F2, etc. keys as standard function keys in Keyboard settings.
What is the Fn key for? +
It is a hardware modifier handled by the laptop's controller. It switches keys between their printed function and their secondary function, such as volume, brightness or the numpad overlay.
Why do the media functions on my F-keys do nothing? +
The laptop's hotkey driver or utility is missing. Install the keyboard hotkey, chipset or system event driver from the manufacturer's support page for your exact model.
Do function keys work in the BIOS? +
Yes. F1 to F12 always act as function keys in the BIOS or UEFI screen regardless of the Fn lock state, which makes it a good place to confirm the keys themselves work.