Why can I switch monitor inputs but not switch back?

Input switching depends on both the monitor’s command support and whether it accepts commands from the connection sending them. A successful switch away from your Mac does not guarantee that the monitor will keep accepting commands from that now-inactive input.

First try switching back from the computer on the currently active input, if it has suitable display-control software. Some monitors accept commands only from the active input. Others have different restrictions. Keep the monitor’s own input selector available while checking this.

If an input-source keyboard shortcut does nothing, try the same input in the display’s Input Source menu. If neither works, investigate the monitor’s command support, connection and configured input value before changing the shortcut. If the menu works, check that the shortcut is assigned to the intended display, input and controller.

Check the input command

BetterDisplay’s input list contains common assignments, not a detected inventory of your monitor’s ports. If a command does nothing or selects the wrong port, check the monitor’s supported values and whether it uses an alternate command.

Open Settings > Displays > [display] > Device Control > DDC Control > Input Sources…. For compatible LG monitors, LG alt selects a different input-control command. The default list includes DP 2 / USB-C (LG alt) with value 209 and HDMI 2 (LG alt) with value 145. Try the entry documented for your model. A USB-C label does not imply that every LG monitor uses the same value.

For raw CLI commands, the alternate transport and alternate input command are separate choices: the LG alternate input path uses ddcAlt with vcp=inputSelectAlt. Selecting an alternate input value while still using the standard inputSelect command is not the same operation. Prefer the configured LG alt input entry when testing through the app.

Use Customize input source list for this display to edit values, labels and menu visibility. Merely renaming a row does not change the command or add monitor support. See DDC input-source configuration.

If video switches but a monitor’s USB hub stays with the other computer, check the monitor’s own KVM settings and USB-upstream-to-video-input assignments. A standard DDC video-input command does not separately configure the monitor’s USB routing. Correct video switching therefore does not prove that the keyboard and mouse will follow it.

If the active connection rejects the correct command, BetterDisplay cannot guarantee switching through it. Use the monitor’s controls or another supported control path. A successful result on one model does not establish support for a related model.