How to send Ctrl-Alt-Delete and other intercepted shortcuts through a KVM

Press Ctrl-Alt-Delete in a KVM web page and, on Windows, your own machine opens its security screen. On a Mac, Cmd-Q quits the browser and Cmd-Tab switches apps. The target computer never sees any of it.

Why the shortcut never arrives

Operating systems reserve certain key combinations for themselves and handle them before any application, including a browser, is told a key was pressed. Windows takes Ctrl-Alt-Delete and the Windows key. macOS takes Cmd-Tab, Cmd-Space, Cmd-Q in most contexts, and the Mission Control and Spaces gestures. The browser also keeps a few for itself, such as Cmd-W and Cmd-T.

KVM web interfaces work around this with buttons that inject a chord as a whole. That works, but it means the key you reach for by habit does something else first, and there is no button for every chord.

What a native client can do differently

A native app can ask the operating system for permission to capture keyboard events before the system acts on them. On macOS this needs an Accessibility permission and an event tap; the app sees every key, decides whether it belongs to the remote computer, and swallows it locally if so. That is how KVM Remote’s Capture System Shortcuts mode passes Cmd-Tab, Spotlight and Spaces to the target.

Because that mode also removes your normal way of switching apps, it is an explicit choice for the session and one fixed chord always gives control back: Control–Option–Command–Escape releases the keyboard and pointer, ends any running macro, and returns every key you were holding. Capture also pauses on its own when a local menu or dialog opens, when the window loses focus, and when secure input is active in a password field.

The three keyboard modes

KVM Remote on Mac offers a Keyboard menu in the console with three options:

The mode is saved per device. System capture is never restored automatically when you reconnect, so a stray permission never surprises you.

Sending a chord without changing modes

For the occasional Ctrl-Alt-Delete you do not need to capture anything. The shortcut bar under the video and the Send Special Keys menu send common chords as a single action: Ctrl-Alt-Delete, Alt-Tab, Alt-F4, Cmd-Q, Command-Option-Escape, Print Screen and the lock-screen combinations for Windows, Mac and Linux. In Keyboard Preferences, choose a Mac, Windows or Linux profile to put the relevant buttons first, and add per-device bindings so a local shortcut sends a different chord on the target.

Macros go further: an editable sequence of keys with delays, which is how you script a login or a repetitive BIOS change. If a macro is cancelled part way, held modifiers are released so the target is not left with Ctrl stuck down.

On iPad and iPhone

Touch devices have no system-shortcut problem because there is no hardware keyboard to intercept. KVM Remote shows an integrated remote keyboard for typing, and the same shortcut bar and special-keys menu for modifier chords. With a hardware keyboard attached to an iPad, Command shortcuts are forwarded to the target while the console has focus.

See the supported devices for which backends accept keyboard input, which today is all of them.