Mod Organizer (MO) is specifically designed for people who like to experiment with mods and thus need an easy and reliable way to install and uninstall them. Mod Organizer 2 is a mod manager created by Tannin to support 64-bit games like Skyrim Special Edition and Fallout 4 in addition to all the 32-bit games MO1 already supported.

Can I use MO for multiple games like Skyrim and Fallout New Vegas?

Yes. MO supports running multiple games by configuring separate "instances." You select the game in the dropdown, create a new instance for each title, and MO manages mods and load orders independently for each one. That way, mods for one game won't interfere with another.

How can I categorize my mods visually in MO?

MO allows you to assign mods to predefined or custom categories and insert "separators" in the mod list. These help organize mods visually but don't affect load order – only the Plugins tab determines the actual load sequence.

How do I back up my load order and mods for use on another system?

Load orders are stored within your MO instance, and mods themselves are found in the mods folder inside your ModOrganizer directory. You can simply copy the entire mods folder and the accompanying load order files to your new system, then restore them in MO to preserve your setup.

Is it normal for MO to show a message like "waiting on application to close before exiting"?

Yes. When launching a game through MO, it will display such a message because MO must remain active to manage mods and cleanup after the game exits. It's expected behavior and not an error.

Need Help?

Discord is the preferred means of contacting someone on the team when you run into problems or have questions about MO2. The Mod Organizer 2 Dev server can be accessed through this invite link.

GitHub is used as our issue tracker. This is used to document and discuss serious issues with MO2 and possible feature requests for the future. While the GitHub issue tracker is open to the public, we ask that you refrain from creating issues unless asked to. You can usually be helped much quicker by jumping on Discord and asking us directly.

Mod Organizer 2 is an open project in the hands of the community, there are problems that need to be solved and things that could be added. MO2 really needs developers and if you have the programming skills and some free time you can really improve the experience of the modding community.

What's New

Windows 10 1809+ or Windows 11 are now required due to the upgrade to Qt 6 and Python 3.11.
Microsoft Visual C++ Redistributable 14.40.33810.0 required.

Starfield Creation Support

Various fixes and improvements for compatibility with the Starfield Creation update.

  • Added new core plugins to the primary plugins list
  • Utilize Starfield.ccc to 'fix' the load order of core plugins
    • By default, Starfield now loads core plugins after plugins.txt unless required by a dependent plugin
    • This forces the plugins to a default early load order, making the plugin memory addressing easier to predict and less prone to unintended record conflicts
    • The file is written to the active profile and virtualized to the game and My Games directories
  • Removed various now-irrelevant checks
    • Plugins.txt Enabler is obsolete
    • Light-flagged plugins no longer generate warnings
    • Remove overlay-flag checks until such time as they actually become relevant
  • Added support for new 'medium'-flagged plugins
    • These use FD memory addresses which will display in the plugin list
    • A warning will display if a plugin has both a light and medium flag in the header as this could indicate record reference corruption and could break the game
  • Added creation kit to default executables
  • Updated save parsing to handle the newer save format
  • Added support for Creations parsing from ContentCatalog.txt
    • Creation mods pull both names and file lists from the content catalog
  • BSA Packer now supports Starfield archive formats
    • Dummy plugins are now saved as light-flagged ESMs
  • LOOT support is now automatically enabled with the addition of libloot 0.23.0

Bethesda Game Updates & Fixes

  • Add detection for Skyrim VR light plugin support SKSE plugin (#29)
  • Allow TTW to pull Nexus categories from FNV
  • Still need a better solution for categories from secondary game sources
  • Allows previewing and parsing the new BA2 versions of Fallout 4

Other Games

New

  • Dungeon Siege
  • F1 23
  • Final Fantasy VII Remake
  • Metal Gear Solid 2 & 3
  • Need for Speed: High Stakes
  • Test Drive Unlimited 1 & 2
  • The Witcher 2
  • Tony Hawk's Pro Skater 3, 4, Underground, Underground 2
  • Trackmania United Forever

Updated

  • Black & White 2
  • Cyberpunk 77
  • Subnautica 2.0
  • Valheim

Plugin List

  • ESL plugin files are no longer displayed in the plugin list for games that don't support them (#2026)
  • Removed the strike-through appearance for dummy plugins and replaced it with a flag icon (empty box) (#1941)
  • Speed improvements for plugin list refresh (#2046)

Others

  • USVFS can now ignore specified directories and file patterns (usvfs#61, #2033)
  • By default .mohidden files and .git directories are ignored
  • Files from BSA archives can now be previewed (provided the corresponding plugin supports the feature) (#2056)
  • Custom themes can now define a different base-style by putting a /* mo2-base-style: Fusion */ comment at the start of the .qss file (#2072)
  • Added button to open log directory from diagnostic tab (#2028)

Bug Fixes

  • Fix crash if no Nexus category is mapped to a MO2 category in the category editor when closing the editor
  • Fix an issue preventing MO2 to correctly authenticate to Nexus when a download is requested but MO2 is not started
  • Python
  • Fixes crashes with some characters in strings, e.g., emoji characters (#120)
  • Isolate MO2 python from system-installed python modules (fixes startup issues with python plugins) (#121)

Development

MO2 Plugin Interface

  • Add displayGameName() and lootGameName() to the game plugin interface (uibase#141)
  • Support for displaying preview from memory data (uibase#153)
  • Add IPluginPreview::supportsArchive() and IPluginPreview::genDataPreview()
  • Non-game third-party plugins can now register custom mod content or mod checker. (uibase#146)
  • Expose mobase.INVALID_HANDLE_VALUE to Python plugins (#131)

Others

  • Improved debug support (mob#136, mob#137)
  • Drop fmtlib for std::format (uibase#143)

Updated dependencies

  • 7zip 24.05
  • boost 1.85.0
  • libloot 0.23.0
  • openssl 3.3.0
  • Qt & PyQt 6.7.1
  • Python 3.12.3
  • spdlog 1.14.1
  • zlib 1.3.1
  • explorer++ 1.4.0
  • usvfs 0.5.0