UAssetGUI

UAssetGUI is a free tool for low-level examination and manual modification of Unreal Engine game assets. It supports .uasset, .umap, .usmap, .utoc and .ucas files, as well as JSON. The Windows application can also be run on Linux through Wine; the project documents Linux setup steps and names Wine 11.0 as the version used for those instructions. Command-line arguments can export and import UAssetAPI JSON without opening the graphical interface, and C# scripts can extend the program. Portable mode, available from v1.1.0, keeps configuration and saved mappings in a Data folder beside the executable. That release also added opening and saving .utoc and .ucas containers with built-in retoc integration. Pre-built binaries and an experimental latest-commit build are available from the repository’s Releases page. Release notes report support for Unreal Engine 5.6 and 5.7. The project uses the MIT License, which provides the software without warranty. Its maintainer announced retirement from development, while noting that future contributions or releases could come from others.

UAssetGUI offers asset inspection and modification alongside command-line JSON handling and C# customization. Check its format and compatibility limits, and note that Linux setup uses Wine.

It suits users who need to examine or modify Unreal Engine assets by hand, including those working with the listed file formats or JSON. Linux users should be prepared to use Wine.

UAssetGUI is a free utility for working directly with Unreal Engine asset files, best suited to modders and other users comfortable with low-level asset editing. Its blend of GUI work, JSON command-line operations, and C# scripts is useful within its supported formats, but it is not a universal Unreal archive editor.

Overview

The tool is built for examining and modifying game assets by hand, not for a broad game-development workflow. It supports .uasset, .umap, .usmap, .utoc, .ucas, and JSON. That range covers individual assets as well as containers, but compatibility depends on format and Unreal Engine version: the v1.0.0.0-alpha.8 notes say UE 5 .pak support did not include IO store or Zen assets.

Pre-built binaries are available from the Releases page, alongside an experimental build from the latest commit. The experimental build may appeal to users seeking recent changes; a standard release is the more straightforward starting point. The v1.0.0.0-alpha.8 notes also report that maintainer atenfyr retired from UAssetGUI development, though future contributions or releases from others remained possible. That makes future maintenance less certain for workflows that depend on ongoing fixes.

Key features

GUI, command line, and scripts

The graphical interface supports direct inspection and modification. Command-line arguments can import and export UAssetAPI JSON without opening the GUI, which suits workflows that need those specific conversions; it does not turn the program into a general-purpose command-line asset processor. Users who can write C# can also extend its behavior with custom scripts, trading convenience for the effort of creating and maintaining their own additions.

Containers and portable mode

Version 1.1.0 added opening and saving .utoc and .ucas containers through built-in retoc integration, extending the tool beyond individual asset files. Portable mode, also available from v1.1.0, keeps configuration and saved mappings in a Data folder beside the executable. That can help users keep settings with a particular copy of the program.

Compatibility and support

Release notes report support for Unreal Engine 5.6 and 5.7, while earlier notes describe some engine support as rudimentary or limited. Users should match the tool’s compatibility to the specific game and asset formats they need; the stated exclusion of IO store and Zen assets from UE 5 .pak support is a meaningful boundary. Bug reports are invited through the issues page. Reports about assets that fail binary equality need sample assets, the game name, the Unreal Engine version, and a mappings file when needed; users seeking help should be ready to provide that context.

Pricing

UAssetGUI costs nothing under the MIT License. There is no paid tier or trial to weigh against the free plan. The license permits use, copying, modification, distribution, sublicensing, and sale subject to its conditions, and provides the software as is without warranty. This suits users who want an unpriced tool and the freedom to adapt it, but it does not come with a warranty.

Platforms

UAssetGUI runs on Windows. Linux users can run the Windows executable through Wine; the project documents setup steps tested with Wine 11.0. That is a workable route for Linux users willing to configure Wine, but it is less direct than native platform support. The documented platforms do not include macOS.

Who it's for

UAssetGUI fits modders and technically confident users who need to inspect or modify Unreal Engine assets by hand, especially when their workflow benefits from JSON import or export, C# customization, or .utoc and .ucas handling. It is a weaker fit for users who need guaranteed support across Unreal formats, a native Linux application, or confidence in a continuing stream of maintenance.

Pros and cons

Pros

• Free and MIT-licensed: users can work with and modify the software without a purchase price, within the license’s conditions.
• Several useful workflows: a GUI, JSON command-line import and export, and custom C# scripts give technically inclined users options beyond manual editing.
• Container support: built-in retoc integration opens and saves .utoc and .ucas files from v1.1.0.
• Portable mode: configurations and saved mappings can travel beside the executable in a Data folder.

Cons

• Format and version limits: UE 5 .pak support in the cited release excludes IO store and Zen assets, and other support has been described as limited.
• Linux requires Wine: users must run the Windows executable rather than a native Linux build.
• Maintenance uncertainty: the maintainer announced retirement from development, leaving future releases or contributions to others.
• No warranty: the MIT license distributes the software as is.

Alternatives

For a broader set of options, browse Game Modding Tools.

• FModel is a free, Windows-only option with code its project describes as open and reusable under license conditions; consider it if that is a better fit than UAssetGUI’s supported workflows.
• QuickBMS is a free, open-source, multiplatform tool; choose it if that combination better suits your needs.
• WolvenKit is free, open source under GPL-3.0, and described for research and educational use; consider it if those terms and its Linux and Windows support fit your use.
• NetRadiant-Custom is a free, open-source level editor with ready-to-use release packages; choose it for that level-editing role.
• OpenMW-CS is a free, open-source construction set for the OpenMW game engine; choose it for work in that engine instead.
• xEdit is a free Windows option; consider it if you want an alternative without a stated price or usage limit.
• Arma 3 Tools is free for non-commercial use, while commercial use requires Bohemia Interactive permission and acceptance of its tools EULA; choose it if those terms suit your use.
• Minecraft Launcher is a free launcher across Android, iOS, Linux, macOS, and Windows, but accessing games requires ownership or a time-limited demo; it serves a different purpose.

Verdict

Look elsewhere if your target format falls beyond its compatibility limits, you need native Linux support, or continued maintenance is essential.