Skyrim Special Edition / Anniversary Edition

Skyrim Special Edition (skyrim-se) and Anniversary Edition (skyrim-ae) are modde’s most complete, end-to-end-tested titles. They share this guide because they are the same game build: identical Steam App ID, install directory, INI files, archive formats, and Nexus domain. The Anniversary Edition is the Special Edition plus Creation Club content, so everything below applies to both ids unless explicitly noted.

Both are marked Done in the supported-games matrix: the scanner, conflict detection, and save tracking are all shipped and user-reachable, and the Wabbajack + home-manager install path described at the end is modde’s strongest worked example.

Engine and overall status

skyrim-ae is registered as a distinct game so you can target it explicitly, but launcher detection reports skyrim-se by default because AE reuses the SE Steam app and install directory. When in doubt, use skyrim-se; pick skyrim-ae only if a modlist or collection demands the AE id specifically.

How modde detects the install

modde locates Skyrim through its launcher ids, then derives the per-user data paths from the Steam App ID. On Linux and macOS Skyrim runs through Proton/Wine, so those paths live inside the compatibility prefix; on Windows the game runs natively and the same paths are their native Windows locations.

• Steam. modde resolves 489830 and the Skyrim Special Edition directory under your Steam libraries. Heroic GOG/Epic ids are not set for Skyrim SE/AE (it is a Steam title), so detection is Steam-based.

• Proton prefix (Linux/macOS). Save and plugins.txt paths are read from the Proton compatibility prefix keyed by App ID:

  <steam>/steamapps/compatdata/489830/pfx/drive_c/users/steamuser/...
  

For Wabbajack lists and any modlist that references the installed base game, you should still point modde at the game directory explicitly with --game-dir (CLI) or gameDir (home-manager) — see Linux/Proton notes and known gotchas.

Mod directory and deploy strategy

Every Bethesda title deploys into the game’s Data/ directory. modde computes the mod directory as <install>/Data and stages mod content there. The deploy itself is symlink-based, consistent with all Bethesda games, so the game’s own Data/ stays a virtual composite of the active profile rather than a destructively merged folder.

Two file classes get special treatment:

• Loose files (meshes, textures, scripts, INIs) are linked into Data/ under their relative paths.
• Archives (.bsa, .ba2) are deployed as-is, not extracted, because the Creation Engine loads them natively. They are placed directly into Data/.

modde recognizes a “bare” extracted layout — a folder that already looks like a Data/ tree — by these root markers, matched case-insensitively:

• Root directories: data, meshes, textures, scripts, interface, sound, music, materials, seq, shadersfx, strings
• Root file extensions: esp, esm, esl, bsa, ba2

This lets modde correctly stage both Data-rooted archives and FOMOD output without you having to flatten them by hand.

See Deployment for the general symlink model and how overwrite/overrides priority works.

What scanning finds

The Skyrim scanner walks Data/ and reconstructs your installed mods, using plugins.txt as the authoritative source of load order and enabled state.

It works in two passes:

1. Authoritative pass. Every plugin listed in plugins.txt that actually exists on disk is emitted as a discovered mod (plugin/<filename>, confidence 0.95). For each plugin stem, the scanner also pulls in companion archives that share the stem — both <stem>.bsa/<stem>.ba2 and the <stem> - Textures.bsa/.ba2 texture-archive convention.
2. Unmanaged pass. Any .esp/.esm/.esl in Data/ not already seen via plugins.txt is emitted with lower confidence (0.8) so disabled or externally-dropped plugins still surface.

Plugin extensions recognized: .esp, .esm, .esl. Archive extensions paired with a plugin: .bsa, .ba2. Each discovered file records its Data/-relative path and size.

See Scanning for how discovered mods feed adoption and stale-duplicate detection.

Conflict classification specifics

Skyrim uses the Bethesda collision classifier, which assigns a severity to every overlapping file by extension — and, crucially, indexes the contents of .bsa/.ba2 archives so two mods that ship conflicting files inside archives are still flagged.

So two mods overwriting the same .dds are a cosmetic (last-wins, usually safe) conflict, while two mods providing the same plugin record or compiled script (.pex/.psc) or native DLL are flagged as dangerous and surfaced prominently. Archive contents (.bsa/.ba2) are read and merged into the collision map, so the analysis is not limited to loose files.

See Conflicts for how severities drive the conflict report and resolution order.

Save tracking

Save tracking is Done for Skyrim SE/AE. modde reads saves from the Proton prefix:

<steam>/steamapps/compatdata/489830/pfx/drive_c/Users/steamuser/Documents/My Games/Skyrim Special Edition/Saves

What it captures and fingerprints:

• It tracks *.ess save files (and *.bak are recognized but skipped as backup copies). The Skyrim .skse co-save written alongside each .ess is explicitly excluded from tracking — it is a SKSE side file, not a save of record.
• For each .ess, modde parses the binary header (magic TESV_SAVEGAME) and extracts the save number and character name, producing labels like Lydia — Save 14. If the header is unreadable or has the wrong magic (e.g. a save from another game dropped in the folder), the file is still captured but without a label.
• Slot category is inferred from the filename: Autosave* → auto, Quicksave* → quick, everything else → manual. A multi-save capture is summarized grouped by character (e.g. Lydia (slots 14, 15); Orc Mage (slot 7)).

Save profiles are enabled for Skyrim, so saves are captured per modde profile — letting you swap modlists without cross-contaminating character saves.

This save fingerprinting matters because Skyrim saves bake in your active plugins: removing or changing a save-breaking mod can corrupt or invalidate an existing character. modde treats the following extensions as save-breaking, which is what triggers a save fingerprint before a destructive change: .esp, .esm, .esl, .pex, .dll, .psc. Cosmetic-only changes (.nif, .dds, .bsa/.ba2, audio, etc.) do not.

See Saves for the general capture/restore workflow.

Plugin and load-order handling

Skyrim is one of the few engines with full plugin/load-order support in modde.

plugins.txt

modde reads and writes the standard Bethesda plugins.txt format inside the Proton prefix:

~/.local/share/Steam/steamapps/compatdata/489830/pfx/drive_c/users/steamuser/AppData/Local/Skyrim Special Edition/plugins.txt

Format rules: a leading * marks a plugin enabled, no prefix means disabled, and # lines are comments. modde-written files start with a generated header comment (# This file is generated by modde. Do not edit manually.).

modde keeps plugin load order separate from mod install priority — “which mod’s files win on disk” is independent from “which .esp loads first” — mirroring MO2’s dual-pane model.

LOOT sorting

modde ships a pure-Rust LOOT masterlist parser (no libloot FFI). It downloads the public LOOT masterlist for Skyrim SE/AE from loot/skyrimse and converts its rules to modde’s internal load-order rules:

• after → load-after rule
• requires → load-after rule (and a missing-master signal if absent)
• incompatible → incompatible-pair rule

Rules are generated only for plugins that are actually in your active set, and matching is case-insensitive. skyrim-se and skyrim-ae share the same masterlist URL.

modde loot sort --game skyrim-se

Plugin diagnostics

modde reads the binary TES4 header of each active plugin (only the first ~1 KB) to run two Skyrim-specific checks plus a shared one:

The Form 43 check is gated to skyrim-se/skyrim-ae specifically, since the Oldrim-vs-SSE plugin format distinction is unique to Skyrim. ESM/ESL flags are read from the same header.

modde loot validate --game skyrim-se

Installer specifics

• FOMOD. Scripted and basic FOMOD installers are supported; FOMOD output is recognized as a Data/-rooted layout via the bare-layout markers above, so the selected options stage correctly into Data/. See the FOMOD installer guide.
• BSA/BA2. Archives are deployed as-is into Data/ and indexed for conflict analysis — they are never unpacked.
• Wabbajack. Skyrim SE is modde’s best-supported Wabbajack target. modde parses Wabbajack manifests, including GameFileSourceDownloader entries (local vanilla game files referenced by the list), Wabbajack CDN authored-files archives, Nexus downloads, and ModDB-style mirror pages. See Wabbajack and the worked example below.
• REDmod / pak / SMAPI do not apply to Skyrim — those are Cyberpunk, UE4/5, and Stardew constructs respectively. Skyrim’s content model is loose files plus .bsa/.ba2 archives plus .esp/.esm/.esl plugins.

Gaming tools that matter for this title

• Proton. Skyrim SE/AE run under Proton; modde derives its save and plugins.txt paths from the Proton prefix automatically once the game is installed.
• SKSE (Skyrim Script Extender). Many mods depend on SKSE. modde does not install SKSE for you, but you can register the SKSE loader as a named executable and launch it through modde — see the executable-management workflow (modde tool add-executable / modde exec) in the tools guide.
• OptiScaler. modde ships no OptiScaler profiles for Skyrim (optiscaler_profiles is empty for both ids); OptiScaler/upscaler tooling is relevant to the UE4/5 titles, not Creation Engine Skyrim.

Linux/Proton notes and known gotchas

These notes concern the game’s runtime on Linux and macOS, where Skyrim runs through Proton/Wine. On Windows the game runs natively, so the prefix-specific points below do not apply — saves, plugins.txt, and INI files live at their native Windows locations. modde itself runs natively on all three platforms.

• --game-dir / gameDir is required for vanilla-referencing modlists. Many Wabbajack lists — Legends of the Frost is the canonical example — reference vanilla Skyrim Data files as install inputs (GameFileSourceDownloader). modde must read and hash-verify those local game files before staging the list, so you have to point it at the installed game directory. Without it, the install fails with a clear missing---game-dir error rather than silently producing a broken profile.
• installMode = "await-game" (home-manager). You can declare a Wabbajack profile before Skyrim is installed. In await-game mode, activation prints the next step and exits successfully instead of failing; once Skyrim is installed through Steam/Heroic, set gameDir and switch installMode to "auto" (or remove it).
• Authored-files availability. Wabbajack lists can break when their upstream authored-files archives are taken down (HTTP 404). modde runs an availability preflight and fails fast, reporting exactly which authored-file ids are missing, before starting bulk downloads. If you have exact local copies, import them by hash with modde wabbajack import-archive (name-only matches are refused).
• Form 43 plugins. Oldrim-era mods ported carelessly to SE/AE can carry the Form 43 header and crash; run modde loot validate --game skyrim-se to catch them.

Worked example

CLI: install a Wabbajack list and deploy

# Install a Wabbajack modlist, verifying vanilla game files under --game-dir.
modde install wabbajack /path/to/lotf.wabbajack \
  --profile skyrim \
  --game-dir "/path/to/Skyrim Special Edition"

# Sort the load order against the LOOT masterlist and check for problems.
modde loot sort --game skyrim-se
modde loot validate --game skyrim-se

# Deploy the profile into the game's Data/ directory.
modde deploy --profile skyrim --game skyrim-se

If you have local copies of authored archives that were pulled upstream:

modde wabbajack import-archive /path/to/list.wabbajack \
  /path/to/Archive-A.7z \
  /path/to/Archive-B.7z

Home Manager: declarative Wabbajack profile

programs.modde = {
  enable = true;
  nexus.apiKeyFile = "/run/secrets/nexus-api-key";

  profiles.skyrim = {
    game = "skyrim-se";
    installMode = "auto";
    gameDir = "/path/to/Skyrim Special Edition";
    wabbajackList = {
      url = "https://authored-files.wabbajack.org/...";
      hash = "sha256-...";
    };
  };
};

gameDir is required for lists (like Legends of the Frost) whose manifest references local vanilla game files; modde verifies them before staging.

If Skyrim is not installed yet, declare the profile in awaiting mode and fill in gameDir after installing the game through Steam or Heroic:

programs.modde.profiles.skyrim = {
  game = "skyrim-se";
  installMode = "await-game";
  wabbajackList = {
    url = "https://authored-files.wabbajack.org/...";
    hash = "sha256-...";
  };
};

Activation prints the next step and continues; once Skyrim exists, set gameDir and switch installMode to "auto".

Note: a wabbajackList profile cannot also set a nexusCollection — the two install sources are mutually exclusive.

See also

• Supported games
• Installation
• Wabbajack modlists
• Deployment
• Conflicts
• Scanning
• Saves
• FOMOD installers
• Executables & tools
• Troubleshooting
• Parity reference