File locations¶

RustyNES writes to two places: a config directory (one config.toml) and a data directory (per-ROM save state slots). The exact paths come from the directories crate, which follows each OS's standard conventions.

The application identifier used by the resolver is:

Field	Value
Qualifier	`dev`
Organization	`DoubleGate`
Application	`RustyNES`

This produces the paths below.

Linux¶

Follows the XDG Base Directory Specification.

Purpose	Path
Config	`$XDG_CONFIG_HOME/RustyNES/config.toml` (commonly `~/.config/RustyNES/config.toml`)
Save states	`$XDG_DATA_HOME/RustyNES/saves/<rom_sha256_hex>/slot{0..9}.rns` (commonly `~/.local/share/RustyNES/saves/...`)

If $XDG_CONFIG_HOME is unset, it falls back to ~/.config. If $XDG_DATA_HOME is unset, it falls back to ~/.local/share.

macOS¶

Follows the Apple Application Support layout.

Purpose	Path
Config	`~/Library/Application Support/dev.DoubleGate.RustyNES/config.toml`
Save states	`~/Library/Application Support/dev.DoubleGate.RustyNES/saves/<rom_sha256_hex>/slot{0..9}.rns`

Note that macOS uses the same directory for config and data (Apple's convention combines them under Application Support).

Windows¶

Follows the standard %APPDATA% layout.

Purpose	Path
Config	`%APPDATA%\DoubleGate\RustyNES\config\config.toml`
Save states	`%APPDATA%\DoubleGate\RustyNES\data\saves\<rom_sha256_hex>\slot{0..9}.rns`

%APPDATA% typically expands to C:\Users\<username>\AppData\Roaming.

What lives where¶

Config directory¶

A single file:

config.toml — your keyboard bindings, rewind settings, audio sample rate, NTSC filter setting. See Configuration for the full schema.

The file is read once at startup. It's written back whenever you change a persisted setting from inside the emulator — "Save to disk" in the rebind modal, the [ui] toggles (theme, 8:7 aspect, FPS), the run-ahead picker, opening a ROM (updating the recent list), or dismissing the first-run Welcome modal — see Controls and Configuration.

The directory and file are created on demand. A pristine install has no config files; the emulator runs from compiled-in defaults until you change something.

The data directory (below) also holds a per-game/ subfolder of per-game <CRC8>.json config overlays (Mesen2-style per-game overrides — region, mapper, mirroring, DIP switches, and similar), keyed by the ROM's CRC. A per-game file can also live as a sibling next to the ROM itself (Game.json beside Game.nes); when both exist, the per-game/ overlay takes precedence, and the sibling is consulted only when no overlay is present.

Data directory¶

A saves/ subdirectory, then one directory per ROM (named by the ROM's 64-character lowercase hex SHA-256), then up to 10 slot files:

saves/
  3e9c1d...cafe/
    slot0.rns
    slot1.rns
    ...
  4f5a2b...beef/
    slot0.rns

Each slotN.rns is a self-contained save state — see Save states and rewind for the format and behavior.

Per-ROM directories are created on demand, so a pristine data directory is empty.

Alongside saves/, the data directory also gains sibling folders as you use the corresponding features: cheats/<rom_sha256>.toml (Game Genie + raw RAM cheats), movies/ (.rnm TAS recordings), fds-saves/ (writable .fds.sav disk images), and — with the RetroAchievements feature built — ra-progress/. Each is created on demand.

Inspecting on your system¶

To see where your install actually writes (handy when something doesn't work the way the table above suggests), you can verify the directory empirically:

Linux / macOS:

# After saving a state at least once
find ~ -name 'slot0.rns' -path '*RustyNES*' 2>/dev/null

Windows (PowerShell):

Get-ChildItem -Path $env:APPDATA -Recurse -Filter slot0.rns -ErrorAction SilentlyContinue

Moving or backing up¶

The config file is plain TOML — copy it to another machine freely.
Save data is keyed by ROM SHA-256 — as long as the destination machine has the same ROM dump (same SHA-256), the slot files load there too.
Rewind state is in-memory only; it doesn't persist between launches.

To start fresh, delete the relevant directory:

Reset	Action
Default keybindings	Delete `config.toml`
All save states for one ROM	Delete that ROM's directory under `saves/`
All save states ever	Delete the `saves/` directory
Everything	Delete the whole `RustyNES` (Linux) / `dev.DoubleGate.RustyNES` (macOS) / `DoubleGate\RustyNES` (Windows) directory

The emulator regenerates everything on the next launch / save.