NotAlterra/README.md

NotAlterra

Subnautica 2 Save Manager

NotAlterra is an unofficial tool for managing Subnautica 2 save files. It locates your save folders, backs up and restores .sav / .bak files, and lets you inspect the internal metadata of every save.

Not affiliated with Unknown Worlds Entertainment or KRAFTON.

Features

• Auto-locate save folders across Steam, Xbox, Epic, and custom installs
• Recover a corrupted .sav from its .bak backup with rollback
• Create / restore full backups (only savegame_* files)
• Manage UE5 Config .ini files — backup, restore, delete
• Inspect any .sav or .bak file — full GVAS metadata dump
• Slot grouping with Multiplayer / Single Player detection
• Playtime extraction — displays total playtime from save metadata
• Warns on name changes and mode switches before recovery
• Startup reminder to close Subnautica 2 before use
• Transaction log — all actions timestamped to transaction.log
• Cross-platform — Linux and Windows console builds

How to Build

# Linux
cargo build --release

# Windows (from Linux with mingw-w64)
rustup target add x86_64-pc-windows-gnu
sudo apt install mingw-w64
cargo build --release --target x86_64-pc-windows-gnu

How to Run

Download the pre-compiled executable for your platform from the releases page.

Linux

tar -xzf notalterra-v0.1.3-linux-amd64.tar.gz
chmod +x notalterra
./notalterra

Windows

Extract the .zip archive and double-click NotAlterra.exe, or run from a terminal:

Expand-Archive notalterra-v0.1.3-windows-x64.zip -DestinationPath .
.\NotAlterra.exe

You can also extract the .zip using Windows Explorer (right-click → Extract All), then open Command Prompt or PowerShell in that folder and run .\NotAlterra.exe.

Important

Running an unsigned executable on Windows triggers a UAC "Unknown Publisher" warning, forcing you to click "Run anyway" and bypass Windows' safety net. This tool lacks a signature not because it's unsafe, but because services like SignPath Foundation require a well-established CI/CD pipeline, audit trail, provenance documentation, and proven community standing to meet their acceptance criteria.

Usage

Run the binary. On first launch it auto-scans for your save folder. The menu is keyboard-driven:

Key	Action
↑ ↓	Navigate
Enter	Select
Esc	Cancel / Back
Y / N	Accept / Decline in dialogs

Menu

1. Recover save file — pick a backup, preview metadata, overwrite the live save
2. Create full backup — copies all savegame_* files to NotAlterra_Backups
3. Restore full backup — overwrite the save folder from a previous backup
4. Inspect save files — view all GVAS properties of any .sav / .bak
5. Manage UE5 Config (.ini) files — backup, restore, or delete .ini files
6. View disclaimer
7. Exit

Where Files Live

%LOCALAPPDATA%\Subnautica2\Saved\SaveGames\
    savegame_0.sav
    savegame_0.bak
    savegame_0_1.bak
    savegame_1.sav
    ...

Linux (Proton / Steam Deck)

~/.steam/steam/steamapps/compatdata/1962700/pfx/drive_c/users/steamuser/AppData/Local/Subnautica2/Saved/SaveGames/
    savegame_0.sav
    savegame_0.bak
    ...

NotAlterra checks both ~/.steam and ~.local/share/Steam — no manual path change needed for legacy or modern Steam installs.

Important

If the tool cannot locate your SaveGames folder, you can manually override the path by editing the save_path field in config.ini.

Backups are stored in NotAlterra_Backups\ alongside the binary.

config.ini

Created automatically next to the binary:

[alterra]
save_path = C:\Users\...\Subnautica2\Saved\SaveGames
save_scan = 2026-05-31 18:00:00
disclaimer_accepted = true
ini_path = C:\Users\...\Subnautica2\Saved\Config\Windows

Delete config.ini to force a fresh scan on next launch.

Only the disclaimer flag and save-folder paths are stored — no backup state or file metadata is persisted.

Platform Support

• Windows — fully tested and supported.
• Linux — builds and runs, but automatic save-file detection has not been tested on a Linux/Steam Deck install yet. The directory layout should be the same, but feedback and bug reports are appreciated.

Safety

• Runs in your user context — no admin privileges required
• No network connections
• Read-only inspect mode won't touch files
• Pre-restore snapshots created automatically
• .ini delete requires a prior backup

License

MIT — see LICENSE.md.