Clamshell mode guide
Clamshell mode is a great way to use a MacBook at a desk: lid closed, external monitor, keyboard, and mouse. The annoying part is what happens to your windows. Close the lid and windows rearrange onto the external display. Open it again and windows move to the laptop screen, often in an order you did not pick. Every switch means dragging things back.
Short version: closing or opening the lid changes which displays macOS sees, so it moves windows around and does not reliably put them back. Try the free options first. SnapState can save one layout for lid closed and one for lid open and restore each automatically when that display layout appears.
When you close the lid with an external display attached, the built-in screen goes away. macOS generally treats that like a display being disconnected: windows that were on the built-in screen are moved onto the external monitor, and the display arrangement is rebuilt around what is left.
When you open the lid, the built-in display comes back and macOS re-detects everything. It does not reliably send each window back to its earlier display and position, and the built-in screen may become the main display again, so windows often pile up on the laptop screen. If the problem also shows up when the Mac simply sleeps, see windows moving to one screen after sleep.
SnapState is a native macOS menu bar app. Each workspace records the visible windows on the current desktop with position and size, the apps needed to relaunch them, the monitor and display layout, and the active tab URL of each window in Safari, Chrome, Edge, Brave, Arc, and Chromium once Automation permission is granted. Because it knows the display layout each workspace was saved for, the matching display layout trigger is a natural fit for lid open and lid closed. If you undock completely, the monitor unplugged guide covers the monitor connect and disconnect triggers.
SnapState costs $9.99 as a one-time purchase, with a lifetime license for up to three Macs and a 14-day refund. Version 2.5.2 requires macOS 15.7 or later on Apple Silicon and Intel Macs and ships as a signed, notarized DMG rather than through the Mac App Store. It needs Accessibility permission to move windows, and workspace data stays local on your Mac as JSON in ~/Library/Application Support/SnapState/.
SnapState saves and restores only the visible windows on the current desktop, so it does not save or restore macOS Spaces. Firefox is not supported, and only the active tab URL per supported browser window is restored, not full tab sets. It is not a tiling or snapping window manager: it recalls arrangements you made. It requires macOS 15.7 or later.
Closing the lid in clamshell mode removes the built-in display from the setup, so macOS generally moves any windows that were on it onto the external monitor. The whole display arrangement changes at the same time, and macOS does not reliably remember where every window was for each arrangement.
Opening the lid adds the built-in display back. macOS re-detects the displays and can shuffle windows between them, sometimes treating the built-in screen as the main display again, so windows often end up on the laptop screen instead of where they were on the external monitor.
Check the display arrangement and main display in System Settings > Displays for both lid open and lid closed setups, and try Stay by Cordless Dog. Stay has been free since version 1.5.1 and stores window positions for each display combination, restoring them automatically as displays connect and disconnect.
Save one workspace with the lid closed and one with the lid open, then arm each to restore when its matching display layout appears. SnapState moves the saved windows back, relaunches missing apps, and remaps saved frames onto the current displays if the setup differs.
It restores only the visible windows on the current desktop, so it does not save or restore macOS Spaces. Firefox is not supported, only the active tab URL per supported browser window is restored, it is not a tiling window manager, and it requires macOS 15.7 or later.