Mod Error Codes (EB1ModError)¶
This document summarizes the error codes and their causes when mod inspection (compatibility check) fails.
Definition location
Source/BlueModManager/ModSystem/B1Mod.h
Fatal error
When a Fatal error (ConfigError) occurs, the mod is blocked from Manifest saving and activation.
1.Error code list
| Code | Display name | Fatal |
|---|---|---|
ConfigError |
Config Error | :material-alert-circle:{ .fatal } Fatal |
PakFileNotFound |
(No popup) | — |
UcasFileNotFound |
(No popup) | — |
UtocFileNotFound |
(No popup) | — |
PakMountError |
(No popup) | — |
PakUnMountError |
(No popup) | — |
DataPatchError |
Data Error | — |
ShaderCompatibilityError |
Shader Compatibility Error | — |
AssetCompatibilityError |
Asset Compatibility Error | — |
LuaScriptError |
Lua Script Error | — |
OldModKitVersion |
Old ModKit Version | — |
2.Detailed descriptions
ConfigError
Cause: The mod's base configuration file cannot be loaded.
| Trigger | Details |
|---|---|
mod_manifest.json load/parse failure |
Manifest file is corrupted or does not exist |
| Mod name and project name mismatch | Name in manifest differs from .uplugin file name |
.uplugin file load/parse failure |
Plugin descriptor is corrupted or does not exist |
PakFileNotFound / UcasFileNotFound / UtocFileNotFound
Cause: Mod package file structure validation failed.
| Error | Details |
|---|---|
PakFileNotFound |
.pak file does not exist |
UcasFileNotFound |
.ucas file does not exist |
UtocFileNotFound |
.utoc file does not exist |
PakMountError / PakUnMountError
Cause: Pak file mount/unmount runtime failure.
| Error | Details |
|---|---|
PakMountError |
FPakPlatformFile::Mount() call failed — pak file is corrupted or locked by another process |
PakUnMountError |
FPakPlatformFile::Unmount() call failed — already unmounted or references remain |
DataPatchError
Cause: An error occurred while processing the mod's JSON data patch.
| Scenario | Details |
|---|---|
| Source JSON not found | Cannot find the original data (StructTag-based) to patch |
| Named source JSON not found | Cannot find the specified named data source |
| Invalid JSON value | Patch descriptor contains an invalid JSON value |
| Patch descriptor load failure | Failed to load FModPatchDescriptor |
| Patch application error | Patch commands (Add/Remove/Replace, etc.) failed to apply to target data |
| Patch result deserialization failure | Failed to convert patched JSON to struct |
ShaderCompatibilityError
Cause: Shaders included in the mod are incompatible with the current game build.
AssetCompatibilityError
Cause: Mod assets are incompatible with the current game build.
| Scenario | Details |
|---|---|
| Asset Hash JSON missing | Contains MPC assets but hash file is missing |
| MPC GUID mismatch | MaterialParameterCollection StateId differs from the game |
| MPC path invalid/load failure | Asset hash JSON contains an invalid MPC path |
| Material structure hash mismatch | Material parameter structure has changed (e.g. game update) |
| Material path invalid/load failure | Material asset does not exist |
| MFI hash mismatch | MaterialFunctionInstance structure has changed |
| MFI path invalid/load failure | MFI asset does not exist |
| DA exists as pak asset | DataAsset is packaged as a pak asset instead of JSON |
| AnimMontage Notify class load failure | Notify class referenced by montage does not exist |
| AnimMontage Notify property mismatch | Notify class properties differ from the game (added/removed) |
LuaScriptError
Cause: Lua script validation failed for the mod.
| Scenario | Details |
|---|---|
.lua/.luapak mixed usage |
Both formats used simultaneously in one mod |
| Static analysis (luacheck) execution failure | Error occurred while running the analysis tool |
| Analysis result file missing | Analysis output file was not generated |
| Analysis result parse failure | Output JSON file has an invalid format |
| Lua diagnostic error detected | Static analysis found error-level diagnostic results |
- OldModKitVersion
Cause: The mod was built with an outdated ModKit version.
| Scenario | Details |
|---|---|
| ModKit changelist below minimum | The second digit (changelist) of the mod version is below the minimum requirement (11246) |
This check only applies to UE 5.6+ builds.
3.Mod states (EB1ModState)
| State | Description |
|---|---|
Active |
Activated and applied to the game |
Inspecting |
Compatibility check in progress |
Unreachable |
Mod directory is inaccessible |
Broken |
Structure is corrupted |
RuntimeError |
Deactivated due to inspection failure |
AddedInGame |
Mod added in-game |