How to merge all windows on Mac (and which apps actually support it)
Six Finder windows. Four TextEdit documents. A Terminal window per project, each one somewhere different on the screen. macOS has a single menu command that collapses all of it into one window, and almost nobody presses it — partly because it has no keyboard shortcut, mostly because it sits in a menu people never open. Here's how to merge all windows on Mac, which apps genuinely support it, and where it quietly refuses.
The command itself
With two or more windows of the same app open, go to the app's
Window menu and choose Merge All Windows. Every window becomes a
tab in one window. Six Finder windows collapse into one window with six
tabs; your scattered TextEdit documents become one document window you
can ⌃⇥ through.
Undoing it is just as easy, and it's the half people miss: select a tab and choose Window → Move Tab to New Window, or simply drag the tab out of the tab bar. Merging is not a commitment — it's a tidy-up you can reverse for the one window you actually want side by side.
Which apps actually support it
This is where the command gets its reputation for being unreliable. "Merge All Windows" isn't a feature each app implements by hand; it comes free with macOS's document tabs system, and an app only gets it if it uses standard macOS windows. Apps that draw their own window chrome — every Chromium browser, every Electron app — don't participate, even though they may have perfectly good tabs of their own.
| App | Merge All Windows? | What you get |
|---|---|---|
| Finder | Yes | Every window becomes a tab in one window |
| Safari | Yes | All non-private windows merge into one |
| Yes | Viewer windows merge; compose windows merge separately | |
| TextEdit, Pages, Numbers, Keynote | Yes | One window, one tab per document |
| Preview | Yes | One window, one tab per PDF or image |
| Terminal | Yes | One window, one tab per session |
| Maps | Yes | Standard document tabs |
| Chrome, Brave, Edge | No | Use the browser's own tabs; drag tabs between windows instead |
| Slack, VS Code, Discord and other Electron apps | No | Each app's own window model; no native tab bar |
Third-party Mac apps vary, and the honest answer for any given one is a
five-second test rather than a list: open the app, look in View for
Show Tab Bar, and turn it on. If a + appears at the end of the tab
bar, the app uses macOS document tabs and Merge All Windows will work.
No tab bar in the View menu at all, and it won't.
Why "Merge All Windows" is greyed out
When the menu item is there but dimmed, it's one of four things, and none of them is a bug:
- You only have one window. Tabs in a single window don't count — macOS needs at least two separate windows to merge. This is by far the most common cause, and it catches people who already have a tabbed Finder window open and forgot the others were closed.
- The other windows are a different kind. If an app has more than one type of window — Mail's message viewer versus a new message you're writing — only windows of the kind you're currently in get merged. Apple documents this explicitly.
- A window is full screen or minimized. Full-screen windows live in their own Space and minimized ones aren't really on screen, so neither joins the merge. Bring them back to the desktop first.
- One window isn't mergeable. Finder windows opened from a mounted disk image, and various special-purpose panels, sit outside the tab system. Closing the odd one out usually un-greys the command.
Give it a keyboard shortcut
Merge All Windows ships with no default shortcut, which is most of the reason it's unknown. Because it's a plain menu item, you can assign one yourself in System Settings in under a minute — type the menu title exactly as it appears and pick a chord. Do it once, per app or for all apps, and window sprawl becomes something you undo with a keystroke instead of a menu hunt.
Better: stop the sprawl happening
Merging is a cure. The prevention is one setting: System Settings →
Desktop & Dock → Windows → Prefer tabs when opening documents. The
default is In Full Screen Only. Switch it to Always and apps that
support document tabs open new documents as tabs from the start, so
there's nothing to merge later. When you do want a separate window,
⌥⌘N overrides the preference for that one. Our guide to
switching between tabs on Mac covers
living in that tabbed window once you're there.
Where merging stops helping
Merge All Windows is scoped to one app, and that's the ceiling. It will happily turn six Finder windows into one, and it can do nothing about the shape of a real working day: a couple of Chrome windows, a terminal, a Slack window and the Finder window you opened four minutes ago. Those are different apps, and half of them don't support merging anyway.
At that point you don't have a filing problem, you have a switching
problem — the question isn't "how do I stack these" but "get me back to
the window I was just in." macOS is thin here. ⌘⇥ switches apps,
not windows, so it gets you to Chrome and leaves you to work out which
Chrome. ⌘` cycles the current app's windows, with no preview, only
inside that app.
That gap is the reason we built Let's Switch. Hold ⌥ and
tap ⇥ and you get a live preview of every open window, most recent
first, across every app and every monitor — so the window you were just
in is one tap away, whether it's a merged Finder window or one of three
Chrome windows. ⌥` does the same scoped to the app you're in. That
part is free, permanently, with no account and no telemetry. Pro ($9.99,
paid once, up to 20 devices per key) adds an ⌥Space search palette for
fuzzy-finding a window by name when you have too many to flip through at
all. One honest caveat: it works within your current Space, so if you
lean hard on multiple Spaces, check that first.
The two habits fit together. Merge the windows that are really one context, switch straight to whatever's left — and if the remainder needs to sit side by side rather than be flipped between, Let's Tile handles that half.
Frequently asked questions
What is the shortcut for Merge All Windows on Mac? There isn't one by default. Merge All Windows lives in the Window menu of apps that support document tabs, and you can assign your own shortcut in System Settings → Keyboard → Keyboard Shortcuts → App Shortcuts.
Why is Merge All Windows greyed out? Most often because only one window is open — tabs inside a single window don't count. It's also dimmed when the other windows are a different kind, full screen, minimized, or of a type that can't be tabbed.
How do I unmerge windows on Mac? Select the tab you want back and choose Window → Move Tab to New Window, or drag the tab out of the tab bar. Each tab can be pulled out individually.
Can I merge all windows in Chrome? Not with this command — Chromium browsers don't use macOS document tabs. Drag a tab from one Chrome window onto another window's tab bar to combine them manually.
Does merging windows close anything? No. Every window becomes a tab; nothing is closed and nothing is saved or discarded. It's a purely visual reorganisation you can reverse at any time.