CascView

About CascView

CascView is a free Windows utility by Ladislav Zezula for opening the CASC storages that Blizzard games have used since 2014 in place of the older MPQ archives. Diablo II: Resurrected keeps all of its data in such a storage, so this CASC viewer is the usual first step for anyone who wants to look inside the game: it shows the full folder tree and copies any file or folder out to disk. It only reads the storage and never changes the installed game.

What the CASC viewer shows

After you choose Open Storage and point the program at a game folder, it lists the storage like an ordinary file manager. A storage is a whole directory of index and data files rather than a single archive, so the complete installation is needed; individual data files cannot be opened alone. For Resurrected the tree contains a data folder with three main branches: global, which holds the classic data tables and interface layouts, hd, which holds the remastered models, textures and effects, and local, which holds language-specific files, including the game strings. Any selection can be extracted with its folder structure preserved.

How to extract D2R files

Community guides describe the same short routine to extract D2R files. Put the program in its own folder and run the build that matches your system, normally the 64-bit one. Click Open Storage and select the Diablo II: Resurrected installation folder. Open the data folder, select global, hd and local, and press Extract with the default settings. The result appears in a Work folder next to the program. A full extraction needs about 40 to 45 GB of free space and takes a while, so most modders extract only the folders they actually intend to edit.

Using extracted files for modding

Extracted tables and JSON files are the raw material for almost every Resurrected mod. Two launch methods are common. Copying the extracted data folder into the game directory and starting the game with the -direct -txt launch options makes it read loose files instead of the storage. The lighter approach is a mod folder started with the -mod and -txt options, which loads only the files you changed and avoids keeping 40 GB of loose data. Players who simply install finished mods rarely need any of this, because D2RMM reads the game data and merges mods automatically.

Editing what you extract

The viewer does not edit anything, so other tools take over after extraction. Data tables are comfortable to work on in AFJ Sheet Editor or the newer MrSoloz D2R TXT, and game strings in D2RStrEdit.

Loading times and patches

Some players extract the whole data folder only to shorten loading screens, since the game then reads loose files directly. Guides that recommend this also warn that the extraction must be repeated after every game update; otherwise the game runs with outdated files and can show bugs or missing content. Loose-file loading is meant for offline play and modding. If you only want faster loading, weigh the disk space and the maintenance after each patch before committing to it.

Development and compatibility

The program is built on CascLib, the author’s open-source library released under the MIT licence. The library remains actively maintained, with commits as recent as September 2026, and its source handles Resurrected storages, including the static storage layout introduced with the Steam edition of the game. The official page itself is brief and dated: it still lists World of Warcraft, Heroes of the Storm, Diablo III and early Overwatch support and gives no version number, so always take the current build from that page rather than from mirrors.

Limitations

It is a viewer and extractor only: files cannot be modified, replaced or packed back into a storage. It is a Windows program. Some Blizzard games, notably World of Warcraft, do not store file names in the storage and need a separate listfile, although this does not affect Resurrected. Extracted game data is Blizzard’s copyrighted material and should be used for personal modding, not redistributed as a whole.

Who should use it

The tool suits mod authors who need original tables, strings, layouts or assets as a starting point, dataminers checking what changed in a patch and curious players who want to see how the game is organised. Players who only install mods through a manager do not need it, and classic LoD modders should use an MPQ tool instead.

D2 Horadric editorial view

This is the standard way into Diablo II: Resurrected’s data: free, simple, read-only and backed by an actively maintained open-source library from one of the most trusted authors in Blizzard modding. A sparse official page, the lack of any editing features and the size of a full extraction keep it in the middle of our scale, but for D2R modding it is close to essential.