KVM switch guide
When a KVM switch moves your monitors to another computer, the Mac usually loses the video signal and macOS treats the monitors as unplugged. It moves their windows onto whatever screen is left and does not reliably put them back when you switch to the Mac again. SnapState restores your saved layout automatically when the monitors return, or from a shortcut.
Short version: a KVM without EDID emulation looks like a pulled cable to macOS. Try a KVM with EDID emulation or the free options first. SnapState puts your windows back the moment the Mac sees the monitors again.
A monitor tells a computer what it is through EDID, a small block of display information. Many KVM switches stop passing that signal to the computer that is not selected. To the Mac this looks the same as unplugging the monitor, so macOS moves the windows from that monitor to a display that is still connected, usually the built-in laptop screen. If the Mac is a desktop with no built-in screen, windows can end up stacked on a single remaining monitor.
When you switch back, macOS re-detects the monitors as if they were newly plugged in. It is the same behavior described in restoring windows after unplugging a monitor and switching a monitor input, just caused by a KVM button.
SnapState is a native macOS menu bar app. A workspace captures windows on every Space with position and size, the apps needed to relaunch them, the monitor and display layout, and the open tabs of each window in Safari, Chrome, Edge, Brave, Arc, and Chromium once Automation permission is granted. When the KVM hands the monitors back, the armed trigger moves each saved window back and remaps saved frames onto the current displays if the setup differs.
SnapState costs $9.99 as a one-time purchase, with a lifetime license for up to three Macs and a 14-day refund. The current version 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.
Many KVM switches cut the video connection to the computer that is not selected. macOS then sees the monitor as unplugged and moves its windows onto a display that is still connected, often the laptop screen. When you switch back, macOS re-detects the monitor but does not reliably return each window to where it was.
It can help. A KVM with EDID emulation keeps presenting a monitor to the computer that is not selected, so on many setups the Mac does not register a disconnect. Results vary by KVM model, cable, dock, and monitor, so check reviews from Mac users before buying one for this reason alone.
Drag windows back by hand, check the KVM and monitor settings for EDID or input detection options, or try Stay by Cordless Dog, which has been free since version 1.5.1 and restores window positions per display setup automatically.
Save a workspace while the KVM is on the Mac, then arm it to restore when a monitor connects or a matching display layout appears. When you switch back, SnapState moves the saved windows back and remaps frames onto the current displays if needed.
It cannot stop the KVM or macOS from treating the monitor as disconnected; it puts windows back afterwards. It is not a tiling window manager, Firefox tabs are not restored, and it requires macOS 15.7 or later.
See windows after sleep, USB-C hubs and docks, clamshell mode, and a shortcut restore for the moment you switch back.