Guides
Every feature, with a picture of the thing you're meant to click. Each page starts with the one-line answer, so you can leave immediately if that's all you needed.
Getting started
Install it, get past the Windows warning, and find the tray icon.
Switch your audio device
Change the default output or microphone, and set volume per device.
Send one app to a different device
Discord in your headset, the game on your speakers, at the same time.
Connect a Bluetooth speaker
Connect and switch in one click, without opening Settings.
Save a setup as a profile
Store the whole picture — devices, mic, app pins — and restore it in one click.
Bind a hotkey
Switch devices from inside a game, without alt-tabbing.
Use the command palette
Press Ctrl+Alt+S and type what you want instead of hunting for it.
Check controller battery
See what your gamepad has left, and disconnect a wireless one.
Deciding whether to use it at all
Not a guide, but it belongs next to them: Switchboard compared to EarTrumpet and SoundSwitch — what each of the three is genuinely best at, and the cases where one of the other two is the better answer.
Still stuck?
Email me and I'll take a look.
If the app closed on its own, the reason is in
%LOCALAPPDATA%\Switchboard\crash.log — paste that in.