You switch hosts on a KVM. The new computer comes up. The monitors light. Your windows are gone from the left screen, stacked on the laptop, or resized to a different resolution. The cables didn't move. The desk is the same. The operating system thinks the display left.

This is usually EDID. The switch stopped telling the idle computer who the monitor is. The OS treats that as an unplug. When you switch back, it treats the same panel as a new display and rebuilds the desktop.

The rule is simple: if the KVM cannot keep each host talking to the same monitor identity while that host is idle, the layout will not stay put. Counting ports on the back of the switch doesn't change that.

What EDID actually is

EDID is Extended Display Identification Data. It is a small block of identity the monitor sends to the computer. It answers three questions: who I am, what resolutions and timings I accept, and how I prefer to be driven.

The operating system uses that identity to place windows, pick a resolution, and remember which panel sat on the left. Unplug the cable and EDID goes with it. Plug it back in and the OS has to rediscover the display. Windows, icons, and full-screen apps then land wherever the OS thinks a newly attached screen belongs. Often that is the built-in laptop panel.

EDID is not a picture. It is not a Display Settings toggle. It is the handshake that tells the computer a monitor is still there.

Why a KVM without EDID looks like an unplug

A KVM sits between the computers and the monitors. When you switch hosts, the video path moves from computer A to computer B.

A switch with EDID emulation keeps feeding each host a copy of the monitor's identity even when that host is not the active one. Computer A still believes the left and right panels are attached. Computer B does the same. The OS never sees a disconnect, so the window layout stays.

A switch without EDID emulation (or one whose emulator drops the handshake) cuts that identity when you leave a host. Cable Matters describes this class of unit as a hard switch: power, data, and EDID communication are cut off from the previous host after you switch. The idle computer sees the same thing it would see if you pulled the HDMI or DisplayPort cable.

That is why the problem shows up on the computer you just left, and again when you come back. The active host sees a fresh attach. The idle host already wrote the displays off as gone.

Why the windows jump, resize, or pile up

Once the OS decides a display disappeared, it has to park every window that lived there. The usual landing spot is the remaining screen, which on a laptop is the built-in panel. Apps that were tiled across two 4K monitors collapse onto a 14-inch laptop display. Full-screen windows exit full screen. A browser that was on the right monitor opens on the left.

When the same monitor comes back, the OS may restore it at a different resolution or treat it as a new display instead of the one it already knew. Windows then snap to a default arrangement. That is the jump people notice.

This isn't a broken Mac or a broken Windows install. It is the operating system doing what it always does when a monitor unplugs. The KVM created the unplug.

Two monitors showing the same picture on a Mac is a different problem. That is one video stream split two ways, not a lost EDID handshake. This page is about window layout, not mirroring.

When a switch cannot keep the layout

A KVM cannot keep your windows in place if it has no EDID emulation, if the emulator is flaky and drops the identity even briefly, or if the host and OS do not remember the display after a hard disconnect.

The Cable Matters 201085 is the no-emulation case. Cable Matters' product page and knowledge-base article both say the switch does not support EDID. The product page also says the inactive laptop may detect the monitors as disconnected when you switch away. That matches the hard-switch behavior above.

The 201085 is a two-laptop USB-C switch. Each host uses one USB-C cable with DisplayPort Alt Mode. The outputs are HDMI and DisplayPort, rated for dual 4K@60 on Windows or Linux. It doesn't charge the laptops (the Micro-B port only powers the unit and USB peripherals). Cable Matters lists it for laptops, not desktop PCs, Chromebooks, or HDMI and DisplayPort-only sources.

Cable Matters' own pages disagree on which Windows version keeps the layout. The product page says Windows 11 may rearrange displays after switching back, and that Windows 10 usually keeps the layout more consistent. The knowledge-base article says the opposite: upgrade to Windows 11 because that OS stores EDID data and can keep windows where you left them. We have no hands-on. Don't treat either Windows version as a fix. The hardware still has no EDID emulation.

A flaky emulator fails the same way. If the switch claims EDID but the handshake drops for a moment during the switch, the OS still sees an unplug. Persistent emulation means the identity stays up on the idle host the whole time, not only after the picture comes back.

If a listing advertises EDID emulation, confirm it on the manufacturer's spec sheet or FAQ. A marketing line is not the same as a persistent handshake.

What will not restore the layout on a switch that has no EDID:

  • Rearranging the displays in Settings after every switch. That is cleanup, not a stay-put fix.
  • New cables or a different USB-C port. The identity is still cut when you leave the host.
  • An OS upgrade promised by one manufacturer note. Cable Matters' two official pages conflict on Windows 10 versus Windows 11, so that is not a reliable rule.

Where to go next

If you still need to pick hardware or cable a desk, use the pages that already do that work. This page doesn't add a list.

For USB-C host pairings, charging, and Mac display limits, read the USB-C KVM guide for Mac and Windows.

For the Thunderbolt 4 switch, the 201085 no-EDID caveat, and when a USB4 switch is enough, read the Thunderbolt KVM guide for Mac and Windows.

For cable order, first-boot checks, and the usual windows-on-the-wrong-monitor setup issues, read the KVM setup guide for two computers on one desk.

If windows jump when you switch hosts, start with EDID. If the switch does not keep the monitor identity alive on the idle computer, the layout will not stay put.