How to Install D2R Mods with D2RMM

This guide shows how to install D2R mods for offline play with D2RMM, the manager most Diablo II: Resurrected addons are written for. The whole setup takes about fifteen minutes and leaves the game installation untouched: the manager builds a separate mod folder, and the game only uses it when started with the right launch options. Most mods are made for single-player and offline characters. A few visual-only mods, such as some loot filters, are described by their authors as usable online, but Blizzard does not officially support modified files on its servers, so that is at your own risk.

What you need before you start

• Diablo II: Resurrected installed through Battle.net or Steam.
• A Windows PC. Builds for macOS and Linux exist, but the author labels them experimental.
• A Nexus Mods account for downloading the manager and most mods.
• A copy of your save folder, usually Saved Games\Diablo II Resurrected inside your user profile. Make it before the first modded session.

Step 1: set up the D2R mod manager

Download the manager from its official Nexus Mods page and extract the archive to any folder. It is portable, so nothing is installed into Windows, and several copies with different mod sets can sit side by side. Start D2RMM.exe and open the Settings tab. Under General, set Game Directory to the folder that contains D2R.exe; the program warns you if the folder is wrong. Leave Game Data Source on Casc Archive and Output Mod Name on its default. With that, the manager is ready to take mods.

Step 2: add D2RMM mods

Only D2RMM mods, meaning mods written for this manager, will work. Each one is a folder with a mod.json file inside, and there are three ways to add it:

• Extract the download into the mods folder inside the manager’s own folder, so the path looks like mods\StackableRunes\mod.json. If the files end up one folder deeper than that, the manager cannot read the mod.
• Drag a .zip or .7z archive onto the program window.
• Use the Mod Manager Download button on a mod’s Nexus page. This needs the manager registered as the handler for Nexus links, which is done under Settings, Nexus Mods. Downloads started from inside the program are limited to premium Nexus accounts; free accounts download from the website.

If a new mod is missing from the list, use Refresh Mod List.

Step 3: enable, configure and order

On the Mods tab, tick the mods you want. Mods with options show a settings button, where values such as stash size or drop multipliers are changed without editing files. Drag mods to change the load order. Order matters when two mods touch the same file: a mod further down the list works on top of the changes made by the ones above it. Entries marked as data mods are plain file replacements rather than scripted changes, and the program recommends keeping them as high in the list as possible.

Step 4: install and launch

Click Install Mods. The manager reads the original game data, applies every enabled mod in order and writes one combined mod into the game’s mods folder. Repeat this step after every change: a new mod, a different option, a new order or a mod update does nothing until Install Mods has run again.

Then start the game with the Run D2R button. You can also launch it yourself with these options added in the Battle.net game settings or in the Steam launch options:

-mod D2RMM -txt

Starting the game without them gives you the unmodded game again.

Where your characters are

A modded game does not use the normal save folder. With the default settings, characters live in a mods\D2RMM subfolder of the Diablo II: Resurrected save folder, and the Settings tab shows the exact path. This is why existing offline characters seem to be missing on the first modded launch. To continue with them, copy the character and shared stash files from the normal folder into the modded one. Copy rather than move, so the originals stay as a backup.

Updating and removing mods

After a game patch or a mod update, open the manager and run Install Mods again. The mod list menu can check Nexus for newer versions once you are signed in. To go back to vanilla data, use Uninstall Mods or simply launch without the options above.

Be careful when removing mods that add new kinds of items, such as stacked gems or runes. A character still holding those items may fail to load once the mod is gone, so take those items off the character first.

If something goes wrong

• Failed to open CASC storage: usually folder permissions or damaged game files. Check that the game itself still starts. If the error stays, extract the game data with CascView and switch Game Data Source to Pre-Extracted Data.
• Changes are not in the game: Install Mods was not run after the last change, or the game was started without the launch options.
• Antivirus warning: recent builds have been flagged as false positives by some tools. Download only from the official page.
• Anything else: the Logs tab shows which mod failed and why, which is what mod authors ask for in bug reports.

Good first mods

A sensible first setup is small: one storage mod, one loot filter and one or two convenience changes. From the D2 Horadric mods catalog, common starting points are Expanded Stash (16×13), Stackable Runes, D2R Simple Loot Filter, Show Item Level and D2R Tweak Control. Add mods a few at a time and launch the game after each batch, so a problem is easy to trace to the mod that caused it.