Arrow key diagonals not working? How to check

After changing keyboard or input settings, your character or cursor may move up and left, but not diagonally. The cause could be a setting in the game or app, an accessibility option, or a keyboard that does not register that key pair at the same time.

Test the keys outside the app first. The Keyboard Test checks whether each key registers and how many keys work at once, which helps separate a keyboard issue from an app setting.

Test the arrow keys together

1. Open the Keyboard Test on the computer with the problem.
2. Press each arrow key separately. Check that all four register when pressed and released.
3. Press and hold the up arrow, then press the left arrow without releasing up. Repeat with up and right, down and left, and down and right.
4. Try each pair in the opposite order too. For example, hold left first and then press up.
5. Repeat the same combinations in the app where diagonal movement fails. If possible, test in another app or game that uses arrow keys.

Press the keys normally, without using Fn or a laptop shortcut. The Fn key usually does not reach the browser, and laptop shortcut keys are commonly handled by the operating system.

What the result means

Both keys register in the test and in the app

The keyboard can send that diagonal pair. The original problem may have been temporary, or the app may have been using a different control scheme. Check whether the issue returns after changing settings again.

Both keys register in the test, but not in the app

The keyboard is probably working. The app may have changed its key bindings, disabled diagonal movement, or assigned a different action to one of the arrows. Check the app's controls and input settings.

One key fails only when the other is held

The keyboard may not support that combination reliably. Some keyboards have limits on how many keys they can report at once, or which combinations they can report together. Try the same pair on another keyboard or computer to compare.

An arrow key fails even when pressed alone

This points to an individual key, connection, or input problem rather than diagonal movement. Test the key in another browser or app, and check the fixes below.

How to fix it

1. Restore the app's arrow key bindings. Open the app or game's control settings and confirm that up, down, left, and right are assigned as expected. If you recently changed a profile or preset, switch back to the previous one or restore the default bindings.
2. Check accessibility keyboard options. In Windows 11, open Settings › Accessibility › Keyboard. Check whether Filter Keys is on, as it can ignore brief or repeated keystrokes. On macOS, open System Settings › Accessibility › Keyboard and check Slow Keys and Sticky Keys. Turn off an option only if you do not rely on it.
3. Check whether Mouse Keys is enabled. This setting uses the keyboard to move the pointer and can change what arrow keys do in some situations. On Windows 11, check Settings › Accessibility › Mouse for Mouse keys. On macOS, check System Settings › Accessibility › Pointer Control › Alternate Control Methods.
4. Check the app's input mode. If the app has a setting for keyboard, controller, or custom input, select the intended mode. Also check that a controller or another device is not taking control of movement.
5. Reconnect the keyboard. Unplug a USB keyboard and try a different port. For a wireless keyboard, check its battery, reconnect its receiver, or pair it again. Test the arrow combinations after reconnecting.
6. Restart the app, then the computer. Close the app completely and reopen it. If the keys still behave differently across several apps, restart the computer to clear a stuck input state.

A keyboard layout or input language change usually affects letters and punctuation, not arrow movement. If only the diagonals changed, check accessibility options and the app's controls before switching layouts again.

When the keyboard may be the problem

If the same arrow pair fails in the Keyboard Test and in more than one app, connect another keyboard and repeat the test. If the second keyboard handles the pair, the original keyboard may have a rollover limit, a worn key, or a fault in its key matrix, the circuit that detects key presses.

For a laptop, connect an external keyboard to check whether the built-in keys are the cause. If one key still fails alone, or the same combinations fail consistently after reconnecting and restarting, contact the manufacturer or a repair shop. A damaged or limited keyboard may need replacement.

Why diagonal movement can depend on the key pair

Keyboard rollover is the number of keys a keyboard can recognize at the same time. A keyboard may register two arrow keys together but fail with a particular pair, especially if the keys share part of its internal wiring. Testing all four diagonals in both press orders can reveal that pattern.

A browser test can show which key presses reach the page, but it cannot change a keyboard's hardware limits or prove that every app handles input the same way. If all pairs register in the test, focus on the app's controls and settings.