How to save and restore window layouts on a Mac

Why macOS loses your arrangement

macOS stores a window's position as coordinates on a particular display. When that display disappears — you undock, the dock drops the connection, the meeting room projector takes over — the coordinates point at nothing, so the system does the only safe thing and pulls every window onto the screen that is left. Reconnecting does not reverse it, because nothing recorded where things were supposed to be in the first place. The arrangement was never an object; it was a side effect.

The workarounds, and what they cost

• Rearranging by hand. Free, and it works. It also costs the first ten minutes of every morning, and you pay it again after every meeting.
• Snapping tools. A keyboard shortcut per window is faster than dragging, but you are still placing windows one at a time, and the tool forgets everything the moment you stop pressing keys.
• Displays with different arrangements in System Settings. Helps macOS put the displays back in the right relative position. It says nothing about which app belongs where.
• Scripting it yourself. AppleScript and the Accessibility API can move windows to coordinates. You will rewrite the script every time you change desks, because coordinates are exactly the thing that keeps breaking.

What a saved workspace has to store instead

The fix is to stop describing positions and start describing intent. In FAST that object is called a Scene, and it holds:

• Display roles rather than display IDs — "the main screen", "the one to the left" — so a different monitor at a different desk can play the same part.
• Layouts and divider weights, which are proportional, so the same layout is meaningful at 1440p and at 5120×1440.
• Matched app windows, identified by what they are rather than where they were.
• Stacks, so windows that were behind other windows stay behind them.
• Theme, so the workspace looks the way you left it.

Restoring one

1. Arrange your windows the way you want them, once.
2. Save the arrangement as a Scene and give it a name you would actually say out loud — "deep work", "client call", "Friday admin".
3. Restore it from the menu bar, a keyboard shortcut, the Shortcuts app, Siri, a fast://scene/deep-work URL or fastctl scene deep-work.

On restore, FAST re-matches the windows that are already open, launches the apps that are missing, and maps the whole thing onto the displays connected at that moment. If the result is not what you wanted, ⌃⌥Z undoes the entire restore in one step — every Scene restore leaves an Undo snapshot.

What this does not do

A Scene restores geometry and running apps. It does not reopen the specific documents inside those apps — that is each app's own state-restoration job. And FAST never rearranges anything on its own: continuous window rules and arrange-on-launch are opt-in, visible and editable in Settings, and a fresh installation does nothing until you ask it to.