SteamShell

Turn a Windows PC into a console. Boot straight into Steam Big Picture, and run the whole machine from a controller.

Two programs, one codebase, and three ways to run them:

	What it does	Touches your shell?
SteamShell — Shell mode	Replaces the Windows shell entirely. Windows boots, Big Picture appears, you never see a desktop.	Yes
SteamShell — Alongside mode	The same program as an ordinary app. Explorer keeps the desktop and taskbar; you get the Quick Menu, controller mouse, RTSS control and Launcher Cleanup. Steam is not launched unless you ask.	No
SteamShell XFE	The controller half for people running Windows' Xbox Full Screen Experience.	No

Only the first one carries the warning below. It is also the default, because owning the shell is what the program is for — but it is now a choice made at install time, on a checkbox, and reversible from Settings afterwards.

Warning

In Shell mode, SteamShell is a Windows shell replacement. It rewrites the shell registry value, terminates explorer.exe on its restore paths, and takes over the session. Test it on a machine or account you are prepared to restore.

Ctrl+Alt+Shift+E is the emergency permanent restore: it registers Explorer as the shell and closes SteamShell. Learn it before you need it.

Alongside mode and the XFE companion never write that registry value and carry none of this risk. If you are unsure, start with one of those — you can convert to Shell mode later without reinstalling.

The Quick Menu, over Steam Big Picture. Every row shows its live value, so it reads as a status panel as much as a control one. D-pad moves, A selects, Left/Right changes a value without opening anything.

More screenshots — Settings editor, tray menu

Settings editor

Nine categories, every key the INI holds, navigable with a controller or a mouse.

Tray menu

The escape hatch — everything here is reachable with a keyboard alone, which is why the controller learner and its undo live in it.

Full picture tour: every Quick Menu page and every Settings category is in the Wiki.

Why this exists

Steam Big Picture is a good console interface sitting on top of an operating system that is not. The gap shows up the moment something goes slightly wrong, and always in the same way: you need a keyboard and mouse for something that should have been a button press.

• A launcher steals focus mid-game and Big Picture is behind it.
• A game exits and leaves its launcher, its updater and an overlay running.
• You want to change resolution, refresh rate, HDR or audio output — all of which live in Settings apps designed for a mouse.
• A game opens a dialog off-screen, or on the wrong monitor, or 800×600 in a corner.
• You want to cap frame rate to keep a handheld quiet, which means alt-tabbing to RTSS.
• Something needs closing and there is no Task Manager you can reach with a thumbstick.

None of that is Steam's fault, and none of it is fixable inside Steam. It needs something sitting between Windows and Big Picture that watches what is happening and gives you controller-reachable answers.

That is what this is. It started as a focus-fixing script and turned into a shell.

The XFE companion exists because Microsoft shipped their own console front end, and it has the same gap — with one extra problem: XInput reads zeros inside Xbox FSE, so the obvious way to read a controller does not work in the exact place you need it. The companion reads the pad through RawInput instead, and can be taught unfamiliar hardware.

What you get

Getting into the game

• Boots to Steam Big Picture and keeps it in front
• Focus scoring — decides which window really is the game, using shape, CPU and audio, rather than grabbing whatever is on top
• Always Focus list for applications that should win over Steam
• Launcher Cleanup — closes launchers, updaters and overlays after you return to Steam
• Startup programs, launched with the shell
• Optional splash video while everything comes up

Running the machine from the sofa

• Quick Menu — hold L3 + R3. Display mode, resolution, refresh rate, scale, HDR, audio output, frame cap, open windows, and the settings worth changing from a sofa
• Controller pointer, with remappable short and long press on every button
• Task list — switch to or close any window, including force-close
• Current Application — name whatever you were just looking at into an executable list, from the Quick Menu, without typing it
• Windows Start menu and File Explorer on a controller chord

Making the controller actually work

• Two input backends — RawInput and XInput, selected automatically
• Controller Learner — teach it any pad it does not recognise, by pressing buttons, and delete a profile that learned wrongly from a hotkey, the tray or Settings
• Input recovery after sleep, including the case where Windows never tells you the machine woke
• Smooth cursor — velocity scaled by real elapsed time, not a fixed step per poll

Keeping the frame rate sane

• RTSS frame limiter and overlay from the Quick Menu
• Global or per-game profile caps, keyed on the game the scorer identified
• Default-on elevated helper for administrator-window input and protected profile writes, so the main application stays unprivileged

Not painting yourself into a corner

• Setup Assistant — standard, custom or portable install, with shell registration optional and reversible
• Emergency restore on a hotkey, and a Safe Mode launch that keeps Explorer alive
• Health Check and a sanitised diagnostic bundle
• Settings migrate in place across versions, with versioned backups
• Every executable-list field has a Recent… picker offering the last five applications you used — including ones you have since closed

Feature comparison

	Shell mode	Alongside mode	XFE
Replaces the Windows shell	Yes	No	No
Boots to Steam Big Picture	Yes	Optional, off by default	—
Window centring, maximising, exclusions	Yes	—	—
Full focus scoring engine	Yes	—	Lite
Always Focus list	Yes	—	—
Taskbar hiding / desktop blackout	Yes	—	—
Desktop mode	Yes	n/a	—
Splash video	Yes	—	—
Setup Assistant and install modes	Yes	Yes	—
Task list, switch and force-close	Yes	Yes	—
Quick Menu	Yes	Yes	Yes
Current Application → executable list	4 destinations	4 destinations	2 destinations
Recent-application picker in Settings	Yes	Yes	Yes
Controller pointer and mappings	Yes	Yes	Yes
Controller Learner	Yes	Yes	Yes
Input recovery after sleep	Yes	Yes	Yes
Display mode, resolution, refresh, scale	Yes	Yes	Yes
HDR toggle	Yes	Yes	Yes
Audio output switching	Yes	Yes	Yes
RTSS frame cap and overlay	Yes	Yes	Yes
Launcher Cleanup	Yes	Yes	Lite
Startup programs	Yes	Yes	Yes
Health Check and diagnostic bundle	Yes	Yes	Yes
Runs inside Xbox FSE	—	—	Yes
Can be disabled without exiting	—	—	Yes
Portable, nothing registered	Optional	Always	Always

Shell mode and Alongside mode are the same executable and the same settings file — the difference is one key, [Features] ReplaceWindowsShell, and whether Windows starts SteamShell instead of Explorer. Switching between them does not reinstall anything.

The window engine is off in Alongside mode by design, not by omission: that mode assumes a keyboard and mouse are within reach, and a program rearranging windows on an ordinary desktop is an annoyance rather than a help.

Roughly half the settings are shared between the two products, and the build fails if a shared behaviour drifts apart.

The window engine (SteamShell only)

The biggest asymmetry in that table. The standalone shell owns window presentation, so it runs a single coordinated tick that handles geometry and focus together — they are one pass on purpose, because moving a window and deciding what should be in front are the same decision made twice if you split them.

Geometry — centring and maximising

Every visible window is considered, and most are immediately ruled out. A window is only touched if it is:

• titled, visible and in a normal state — already minimised or maximised is left alone
• a real application window — not a child window, menu, tooltip, dropdown or a surface that cannot take focus
• large enough to be an application rather than a popup, if it has no title bar
• not on your exclusion lists

Surviving windows get two independent decisions:

• Centred if it is off-centre by more than a couple of pixels.
• Maximised if it is at least MinWidthPercent of the screen width (default 30%) and the window is actually resizable. A fixed-size dialog is centred, never stretched.

The on-screen keyboard and Steam's own keyboard are skipped, and you can exclude anything else by executable or window class:

[WindowManagement]
MinWidthPercent=0.30
ExcludeExeList=GameBar.exe|YourTool.exe
ExcludeClassList=UnityWndClass|Chrome_WidgetWin_1

It gives up rather than fighting. Each window gets a bounded correction budget inside a rolling window; an application that keeps moving itself back is left alone for a while instead of being wrestled every tick. That is why a stubborn launcher settles rather than flickering.

Administrator windows are handled by the elevated helper. SteamShell itself runs at normal integrity and cannot move a High-integrity window, so it hands those to the small verified helper rather than elevating the whole shell.

Single display assumed. Geometry centres against the primary monitor. SteamShell is built for a TV or a handheld — one screen, one game — and window placement follows that. Game detection is per-monitor as of 2.0.0, because the companion runs in setups the shell does not, so the two differ deliberately rather than by omission.

Focus

The other half of the same tick, driven by the scoring described above — shape, then CPU, then audio, each gate deciding whether the more expensive check is worth running. Geometry changes defer focus for a tick, so the engine never activates a window it is mid-way through moving.

Turn the whole thing off with EnableWindowManagement=false, or pause it temporarily from Settings → Advanced.

Assist Lite (XFE only)

The companion deliberately does not have a window engine. Xbox FSE owns presentation, and a second program moving windows underneath it would be fighting the shell rather than helping it.

Assist Lite never resizes, centres or maximises another application's window. The only geometry XFE applies is the initial window mode of a startup program you asked it to launch.

What it does instead is three narrow, independently switchable behaviours:

Setting	What it does
Game Focus Lite	Keeps the running game in front when something else steals focus
Steam Assist Lite	Brings Steam back to the front when a game exits
Launcher Cleanup Lite	Closes leftover store launchers once no game is running

All three are off-switchable from the Quick Menu, which writes the change immediately — no restart, and no need to open the Settings window.

The safety rules

These matter more than the features, because an assist that misfires inside FSE is worse than no assist:

• It pauses entirely while any SteamShell XFE window owns the foreground, so it can never fight the Quick Menu, Settings or one of its own dialogs.
• The foreground must be stable for ForegroundStableSec (default 30s) before cleanup may run. Nothing is closed during the churn of a game exiting.
• A game counts as running if it is fullscreen or borderless, or if a process is using more than CpuThresholdPercent (default 12%) — which covers a game that has minimised itself. Set it to 0 to use window shape alone.
• Protected processes are never closed, and launcher cleanup only ever targets the list you give it.
• Graceful close first. A hard kill is available but is opt-in and time-boxed.
• The timer only exists when something is enabled. A default install with all three off does no extra polling at all.

[Assist]
EnableGameFocusLite=true
EnableSteamAssistLite=true
EnableLauncherCleanupLite=true
TickIntervalMs=2000
ForegroundStableSec=30
CpuThresholdPercent=12

The same window-scoring code decides which window is the game in both products — it also drives the per-game RTSS frame cap, where picking the wrong window would write your cap into another program's profile and report success.

Download

Latest release → SteamShell.exe

One executable installs both products. It embeds the elevated helper and the XFE companion and deploys whichever you choose through its Setup Assistant.

Verify it if you like — the same binary is committed at releases/2.0.4/current/SteamShell.exe, and its SHA-256 is in releases/2.0.4/RELEASE.md alongside the exact source that produced it.

Getting started

1. Put SteamShell.exe somewhere sensible and run it.
2. The Setup Assistant opens. Choose a product, confirm the detected Steam path, and decide whether to register as the Windows shell.
   • Leave that box ticked for Shell mode — the full takeover.
   • Clear it for Alongside mode: Explorer keeps the desktop and taskbar, nothing is written to the shell registry, and you still get the Quick Menu, controller pointer, RTSS control and Launcher Cleanup.
3. Press Ctrl+Alt+Shift+S for Settings, or hold L3 + R3 for the Quick Menu.

Changed your mind? Settings → Advanced & Logging → "Switch to Shell Mode…" (or "Switch to Alongside Mode…", depending which you are in) converts between them and restarts into the other. Nothing is reinstalled.

Requires Windows 10 or 11. Building from source additionally needs AutoHotkey v2.0.19 or newer, 64-bit.

Hotkeys

Key	Action
Ctrl+Alt+Shift+E	Emergency permanent restore — Explorer becomes the shell again
Ctrl+Alt+Shift+Q	Quick Menu
Ctrl+Alt+Shift+S	Settings editor
Ctrl+Alt+Shift+P	Control Panel
Ctrl+Alt+Shift+R	Reload settings
Ctrl+Alt+Shift+G	Run Game Foreground Assist once
Ctrl+Alt+Shift+I	Re-arm controller input
Ctrl+Alt+Shift+D	Delete the learned controller profile

On a controller: hold L3 + R3 for the Quick Menu, hold View/Back for the pointer, and View/Back + Start for the Windows Start menu.

Documentation

The wiki is the reader-friendly documentation — installing, the Quick Menu, settings, controller mappings, teaching a new controller, and troubleshooting.

In-repo, for depth:

File	Covers
SteamShell/README.md	Full standalone reference
SteamShell/README-XFE.md	Full companion reference
SteamShell/CHANGELOG.md	Every change, by release
STEAMSHELL_PROJECT_OVERVIEW.md	Design decisions and incident write-ups
SteamShell/WINDOWS_TEST_CHECKLIST.md	What to exercise on real hardware

Building from source

Run-SteamShellValidation.cmd

Runs both PowerShell validators, the Python structural replay and controller-profile simulation, native AutoHotkey validation, compiles the helper, companion and installer, runs the installer's quiet self-test, proves the build gate rejects broken and stale output, and only then publishes to current\.

Needs Windows, PowerShell 5.1, and AutoHotkey v2 with Ahk2Exe. To build the installer alone, use SteamShell\Build-SteamShell.cmd.

The build runs only the deterministic /selftest --quiet command mode. Hardware, installation, UAC, RTSS, display, audio, and controller behavior stays in the Windows acceptance checklists.

How this is built

Two programs share one codebase. SteamShell-Common.ahk compiles into all three binaries, SteamShell-Shared.ahk into both main products, and static validators enforce that:

• Exact function manifests — a shared function cannot be quietly copied back into one tree, and a name cannot appear in both.
• A duplicate-detection gate that compares call sequences rather than text, because text is the first thing that changes when a copy is tidied.
• Assertions that pin behaviour, not implementation — the checks describe what must remain true, so correcting a bug does not fail the build for the wrong reason.

SteamShell/DIVERGENT_FUNCTIONS.txt records every place the two products deliberately differ, with the reason — because a divergence nobody wrote down is indistinguishable from a bug nobody noticed.

That is not incidental tidiness. Several real bugs in this project were in code that was already shared and simply wrong in both places, or documented as an intentional difference when it was actually an unported fix. A gate proves two copies agree; it says nothing about whether they are right.

Licence and support

No support is provided. Use at your own risk.

A personal project, shared in case it is useful to someone with the same problem. It replaces the Windows shell — please read the warning at the top before running it on a machine that matters to you.