MHW ModFixer

[size=4][b]Description[/b][/size]
MHW ModFixer automatically repairs Monster Hunter Wilds cosmetic mods that break after an official game update.
Every update can shift the internal structure of character model/material files (mdf2, pfb, user, scn), which breaks costume mods that were working fine before: purple/checkerboard textures, invisible body parts, REFramework [Invalid file]/[Missing File] errors, black screens.
Fixing this used to mean opening Blender + REFramework and patching files by hand, every single time an update dropped.
This tool does that automatically, for both loose-file mods and mods packaged as their own .pak.
Drop in a mod archive, and it reads your currently-installed game version's own files directly, finds exactly which parts of the mod fell out of sync with the current structure, and rebuilds only those parts.
Everything already compatible is left completely untouched.
Anything it can't safely reconcile is left alone and reported instead of guessed at, so it never silently discards a mod's real customization.
The tool also keeps its own safety-verification data current with the game: it checks a fix is actually safe before applying it, and can fetch the latest verification data straight from its source with one click (Settings > Developer Options).
So it doesn't need to wait for a full new release to stay accurate after a game update.

[b]New: Change Target Armor.[/b]
A separate tool (its own button, not part of the repair flow) that relocates a mod from the armor slot it currently targets onto a different armor slot with a matching physics setup, useful when two mods want the same slot.
Pick a mod archive and it detects which slot(s) it uses (a mod can legitimately span more than one, e.g. a main armor plus some incidental extra files), shows which other slots are physics-compatible, and lets you decide per slot whether to move it or leave it as-is.
It verifies the target actually exists in your installed game before touching anything, and it never edits file contents, only renames/relocates, so nothing about how the mod actually looks is ever guessed at.

[b]New: automatic Fluffy page-structure repair.[/b]
Some mod authors' raw releases don't set up modinfo.ini correctly for every included piece, so Fluffy Mod Manager's install-option screen doesn't show all the choices it should (a texture page or outfit variant silently has no way to be installed).
The tool now detects this and repackages the mod into a proper multi-page structure automatically.
No option to toggle, it just happens when needed, and a mod that's already structured correctly is left completely untouched.

[b]Note:[/b]
- [size=4]It doesn't guarantee a 100% repair for all costume mods.[/size]
  (There are so many modders, and each uses different methods.)
- Costume mod means Weapon + Armor costumes. (Yes, most weapon costume mods should be repaired.)
- This is not the work of an expert modder or programmer, so there might be some gaps.
- If anyone wants to modify or improve it, please feel free to do so. (I've even attached an MD file for AI assistance.)
  (I also wanted to mention this in case I'm no longer able to update this mod due to personal circumstances. I hope you understand.)
- Full source code is on GitHub if you'd rather verify/build it yourself:  [url=https://github.com/PoeticJustice79/MHWmodfixer]https://github.com/PoeticJustice79/MHWmodfixer[/url]
- [b][size=4]Download from Github: [url=https://github.com/PoeticJustice79/MHWmodfixer/releases/tag/v0.4] [/url][url=https://github.com/PoeticJustice79/MHWmodfixer/releases/tag/v0.5]https://github.com/PoeticJustice79/MHWmodfixer/releases/tag/v0.5[/url] [/size][/b]

[b]This is not a virus or scam spyware program.[/b]
[quote]That's a known false-positive with PyInstaller-built exes --
the way it self-extracts at runtime looks similar to how some malware droppers behave,
so antivirus heuristics sometimes flag it even though there's nothing actually wrong.
It's not unique to this file; happens to a lot of small PyInstaller tools.

Full source code is now public on GitHub if you want to verify it yourself or build it from source instead: https://github.com/PoeticJustice79/MHWmodfixer

If you trust it, you can restore it from quarantine / add a Defender exclusion for it.[/quote][url=http:][/url]

[size=4][b]Installation instructions[/b][/size]
[list=1]
[][color=#D4D4D8]Download and run the exe — no installer, no Python required, just run it directly.[/color][/]
[][color=#D4D4D8]Drag and drop the mod archive(s) you want fixed into the window (multiple at once is supported).[/color][/]
[][color=#D4D4D8]Confirm your game install path (auto-detected; set it manually if it's wrong).[/color][/]
[][color=#D4D4D8]Pick a save folder once — batch processing runs unattended after that, no per-mod prompts.[/color][/]
[][color=#D4D4D8]Drop the resulting fixed zip(s) straight into Fluffy Mod Manager as usual.[/color][/]
[/list][color=#D4D4D8]Note: [/color]
[color=#D4D4D8]- if your install path contains non-English characters, that can cause errors — an English-only install path is recommended (the tool will warn you if it detects this).[/color]

[size=4][b]Main features[/b][/size]
[list]
[]Reads the live, currently-installed game files directly — no manual pak extraction needed[/]
[]Automatically detects and repairs stale 
[code].mdf2[/code] (material) and 
[code].pfb[/code] (prefab) files[/]
[]Never touches files that already match the current game version[/]
[]Leaves anything it can't safely fix untouched and clearly reported, rather than guessing[/]
[]Batch mode: drop in multiple mods, pick one save folder, and it processes the whole queue unattended[/]
[]Persistent log file saved alongside the program for troubleshooting[/]
[]Multi-language UI (English, Korean, Japanese, Traditional/Simplified Chinese)[/]
[/list]
[size=4][b]Requirements[/b][/size]
[list]
[][color=#D4D4D8][url=https://github.com/praydog/REFramework-nightly/releases]REFramework[/url] with Loose File Loader enabled[/color][/]
[][color=#D4D4D8][url=https://www.nexusmods.com/site/mods/818]Fluffy Mod Manager[/url] (or manual loose-file installation)[/color]
[/]
[/list][b]Version history[/b]

[list]
[]v0.1
Initial test release. Core auto-repair: reads the currently-installed game version's own files directly, diagnoses which mdf2 (material) files are structurally stale, and rebuilds only those.
[/]
[]v0.2
Added an opt-in "force-fix" option for pfb (prefab) pieces that can't be safely auto-verified against the current game. Some mods left these untouched by default, which occasionally caused boot hangs when equipped — this option forces a fix anyway (off by default, verify in-game).
[/]
[]v0.3
Fixed two crash/false-positive bugs in the mdf2 parser found on certain pak-packaged mods (reported by a user, independently verified against the live game before fixing). Added a second opt-in pfb option that preserves mod-added custom parts (e.g. physics chains) the current donor doesn't have, instead of discarding them. Added a progress bar + "please wait" notice during diagnosis/repair. Default UI language is now English.
[/]
[]0.4
Switched distribution from a single-file exe to a folder build with UPX compression disabled, to reduce antivirus/Nexus false-positive quarantines (both are common triggers for unsigned freshly-built executables).
[/]
[]v0.5
Mods packaged as their own .pak file now also get their bundled .pfb/.user/.scn files checked and repaired, not just .mdf2 (materials). Previously these were left completely untouched, which could show as "[Invalid file]" in REFramework with the character rendering invisible even though materials were fine.
Added a field-layout verification check that confirms a repair is actually safe before applying it, instead of trusting a version-ID match alone
found and fixed a real case during testing where that trust alone could crash the game; unverifiable or unsafe cases are now left untouched rather than guessed at.
The pfb "force-fix" option can now also resolve a pak-bundled piece that couldn't be safely verified by replacing it with the current vanilla version.

Also added a post-write check that re-reads a rebuilt .pak and confirms it holds the same entries as the original before finishing.
New Settings → Developer Options → RSZ Snapshot menu lets you see what safety-check data is currently installed, fetch the latest version straight from its source with one click, or import a snapshot someone shares all without waiting for a new MHWmodfixer release.

New
Change Target Armor: relocate a mod onto a different, physics-compatible armor slot (own button in the main window).
Handles mods that span multiple slots at once, deciding each one individually.
Verifies the target exists in your game before touching anything.
Automatic Fluffy page-structure repair: fixes mods whose raw release doesn't show all install options in Fluffy (missing texture/variant pages).
Fully automatic, no toggle needed.

Fixed
Materials could get silently downgraded to a narrower shader variant when the mod's own shader was still fully in use elsewhere in the game.
Caused a confirmed crash on one real mod and silent loss of paint-layer customization on others.
A mod's own gpbf (GPU buffer) references could be overwritten by the donor's.
Caused wrong color/blending on affected pieces.
Already-up-to-date materials were sometimes needlessly rebuilt.
Removed an incorrect "fix" for avp.user cross-slot references.
Those are sometimes deliberate (borrowed-mesh hair-hide data), and rewriting them could break hair hiding.
"Check GitHub for latest data" (Developer Options) now safely merges into the existing verification data instead of overwriting it.
A background-thread error dialog could show the wrong error message under certain failure conditions.
Also included
Optional "Shader migration" repair for mods stuck on a retired shader, verified in-game on real mods.
Off by default, always verify results yourself.
Darker UI theme, color-coded log.
As always: verify any experimental-option result in-game before trusting it.
If something looks wrong, feel free to leave a comment with the mod name and what you're seeing.[/]
[/list]

[size=4][b]Shout outs[/b][/size]
[color=#D4D4D8]Thanks to everyone in the MHWilds modding community for reporting broken mods and testing fixes — this tool exists because manually re-fixing the same handful of mods after every update finally got old.[/color]