How to lock an app window with Touch ID on Mac

Q: Can you lock a single window on Mac?

Not with macOS alone: ⌃⌘Q locks the whole screen. Hushwin locks individual hidden windows, or a whole app, behind Touch ID or your password.

Q: What if someone else knows my Mac password?

Create a Hushwin password in Settings → Security. Locked windows then open only with Touch ID or that password.

What macOS gives you

⌃⌘Q locks the whole Mac. It's safe, but you can't keep working while the private window is protected.
Some apps have their own lock — a locked note, a password-protected folder — but most chat apps, spreadsheets and browsers don't.

There's no built-in way to say "this one window needs my fingerprint".

Lock a window with Hushwin

Look at the window and press ⌃⌘S to make it a hidden window.
Open Hushwin Settings → Hidden windows and click the lock next to it.
Press ⌃⌘E (or the window's own shortcut) to hide it.
To open it, hold the shortcut for about a second and confirm with Touch ID or your Mac password.

Want the whole app locked — every chat window, every document? Turn on Whole app for that entry, and windows the app opens later are hidden and locked too.

What a lock actually does

It stays out of the Dock. It's moved off-screen instead of minimized, so there's no Dock preview and nothing to click. If something else tries to bring it back — the app's Window menu, say — Hushwin hides it again right away and asks for Touch ID; pass it and the window opens. (macOS shows the window before telling Hushwin, so it can flash for a moment.)
Windows already in the Dock are locked too. When you lock a whole app, the windows you'd minimized to the Dock are locked with it. Clicking one there shows it for a moment like above, then hides it again and asks for Touch ID.
Every way of opening it asks. The window's shortcut, "Restore all" or the menu — a locked window always needs authentication.
Attempts are logged. Failed or cancelled Touch ID prompts and attempts to pull the window back appear in the menu with their times. Clearing the log needs Touch ID.
Changing your mind needs you, too. Turning a lock off, narrowing a locked whole app back to one window, removing a locked window and quitting Hushwin while windows are locked all ask for authentication.

Use a Hushwin password instead of your Mac password

A locked window accepts Touch ID or your Mac login password. If other people know your Mac password — a shared family Mac, a colleague who set it up — create a Hushwin password in Settings → Security. After that only Touch ID or that password opens locked windows. Creating or changing it asks for authentication first, and it's stored only as a salted PBKDF2 hash.

Lock windows automatically by title

In Settings → Auto-hide → Auto-lock by title keyword, enter words like salary, HR, payroll or a client's name. A window whose title contains one of them is locked and hidden the moment it appears. Once you've unlocked it, it stays open until you hide it again.

Lock everything except what you're working on

Focus Mode (⌃⌘D) keeps only the apps you choose on screen. Turn on Lock apps that aren't allowed, and every other window stays locked until you turn Focus Mode off with Touch ID.

FAQ

Can you lock a single window on Mac?

Not with macOS alone: ⌃⌘Q locks the whole screen. Hushwin locks individual hidden windows, or a whole app, behind Touch ID or your password.

Can someone open a locked window from the Dock?

No. Locked windows are moved off-screen instead of being minimized to the Dock. If another path, such as the app's Window menu, brings one back, Hushwin hides it again and asks for Touch ID. It can flash for a moment first.

What if someone else knows my Mac password?

Create a Hushwin password in Settings → Security. Locked windows then open only with Touch ID or that password.