# Installing Fusion

## What you need

- **Windows 10 or 11, 64-bit.**
- **A graphics card with DirectX 12** (most from 2016 on). Fusion and your games share it.
- **Enough memory for two games at once.** 16 GB of RAM works for most pairs; Fusion tells you
  how much each scenario uses, and puts games to sleep when memory runs low.
- **The games you want to fuse**, installed. Steam games are found by themselves; others are found
  by their router.

You don't need Steam for Fusion itself, and you don't need administrator rights.

## Download and install

1. Go to [steonmod.com/download](https://steonmod.com/download) and click **Download for
   Windows**. You get `Fusion-Setup-<version>.exe`.
2. Run it. Windows may say **"Windows protected your PC"**: the installer isn't code-signed yet.
   Click **More info**, then **Run anyway**.
3. Answer **Yes** when it asks to install. It takes a few seconds and opens Fusion.

> [!TIP]
> To check the download is the real one, compare its SHA-256 with the one on the download page.
> In PowerShell: `Get-FileHash $env:USERPROFILE\Downloads\Fusion-Setup-0.1.0.exe`

## Where things go

| What | Where |
|---|---|
| Fusion itself | `%LOCALAPPDATA%\Programs\Fusion` (the current version and the one before) |
| Your settings, keys, installed content, crash reports | `%LOCALAPPDATA%\Fusion` |
| Shortcuts | Start menu and desktop: **Fusion** |

Double-clicking a `.fusion` file opens it in Fusion's **Content** screen.

## Updates

Each time it starts, Fusion asks steonmod.com whether there's a newer version. If there is, it
shows what's new and asks first. While it downloads you see a progress bar, and **Cancel** keeps
the version you have. Every update is signed by SteonMod; Fusion refuses one that isn't, and keeps
the version before so it can go back if the new one crashes.

You can change or empty the update address in **Settings → Updates** (empty: Fusion never looks).

## Uninstalling

Open Windows' **Settings → Apps → Installed apps**, find **Fusion**, and choose **Uninstall**.
It removes Fusion, its shortcuts and its file type. It asks before removing your own data
(`%LOCALAPPDATA%\Fusion`) and keeps it unless you say so.

Games that Fusion set up keep their setup until you undo it: in **My Games**, press **Undo setup**
on each one before uninstalling, and they're back as they were. See [My Games](https://steonmod.com/docs/my-games).

## If Fusion crashes

Fusion's launcher notices, saves a report in `%LOCALAPPDATA%\Fusion\crashes\`, and tells you. If
the crash came right after an update, it offers to go back to the version before. Please send the
report along when you tell us what happened ([Fixing problems](https://steonmod.com/docs/troubleshooting)).