When a window appears lost after a monitor is disconnected, first confirm that it is still open. Activate the application, inspect its Window menu, and open Mission Control. Do not create a duplicate until you know the original window is closed.
Bring the window into a selectable state
Choose the window from the application’s Window menu or a window-level switcher. If any edge or title bar is visible, drag it onto the current display. A supported window manager command that moves the active window to a display can help, but verify the target before invoking it.
If the window cannot be selected, reconnect the prior monitor or restore the previous display arrangement temporarily. Move the window to the built-in display, then disconnect again.
Check display configuration
Open Displays settings and confirm whether the Mac is extending or mirroring. Review the physical arrangement and which display is primary. A changed resolution or orientation can leave a restored layout poorly sized even when the window is technically visible.
Prevent repeat loss
Before unplugging, move critical windows to the built-in display or save work and close them. Test any layout snapshot with the disconnected-display case; saved coordinates and current display geometry are not the same thing.
Wallo tracks current window identities rather than screen coordinates. It can help select a discovered window, but it does not promise to relocate an offscreen window or rebuild a layout after displays change.