Download Nucleus Co-Op

Nucleus Co-Op is completely free and open source. Always download from the official GitHub repository to ensure you have the genuine, unmodified application. Never download Nucleus from third-party sites.

Official Download

Nucleus Co-Op Latest Version

Windows 7 / 10 / 11 — Free — Open Source

Download NucleusApp.zip from GitHub

You will be redirected to the official GitHub releases page

Before You Extract

  1. Create folder C:\NucleusCo-op
  2. Add that folder to Microsoft Defender exclusions
  3. Copy the downloaded zip into that folder
  4. Extract using 7-Zip with password: nucleus
Full installation guide

Nucleus Co-Op Version History

v2.4.1 2024 Recommended

Current recommended release. Improved handler API, better ProtoInput stability, Windows 11 fixes, and support for new Goldberg emulator build.

v2.4.0 2024 Previous Stable

Introduced Nucleus UI overhaul, new handler scripting functions, and expanded multi-keyboard support.

v2.2.1 2023 Legacy

Stable release for users experiencing issues with newer versions. Some older handlers were written for this version.

Alpha 8 Mod 2021 Legacy Mod

The Alpha 8 Mod by Mikou27 was a major milestone that introduced ProtoInput. Some older handler guides still reference this version. Use the latest v2.x release instead.

All releases available at github.com/SplitScreen-Me/splitscreenme-nucleus/releases

Download Game Handlers

After installing Nucleus Co-Op, you need handlers for each game you want to play in split-screen. Handlers can be downloaded directly inside Nucleus (click Add New Games) or from the Game setup library website.

Browse Game setup library

How to Update Nucleus Co-Op

Nucleus Co-Op does not have an auto-updater. To update to a new version, you must do a clean installation:

  1. Download the new NucleusApp.zip from GitHub releases.
  2. Create a new empty folder (e.g., C:\NucleusCo-op-new) and add it to Defender exclusions.
  3. Extract the new zip into the new folder using 7-Zip with password nucleus.
  4. Copy your old handlers folder from the previous installation if you want to keep them.
  5. Delete or rename the old Nucleus folder.

Do not extract new files on top of old files — this causes compatibility issues.

Download FAQ

Is Nucleus Co-Op free to download? +
Yes. Nucleus Co-Op is completely free. The developers accept optional Patreon donations but the application will always be free and open source.
Why does my antivirus block or delete Nucleus Co-Op files? +
Nucleus Co-Op includes hook DLLs and the Goldberg Steam emulator, which some antivirus programs (including Microsoft Defender) flag as false positives. These are not malware. Add your Nucleus folder to your antivirus exclusions before extracting.
Where can I download the Nucleus Co-Op Alpha 8 Mod? +
The Alpha 8 Mod is available in the GitHub releases archive. However, the current v2.x releases are significantly improved and recommended over the older Alpha 8 Mod. Only use Alpha 8 if a specific handler requires it.
How do I know if my Nucleus Co-Op version is outdated? +
Open Nucleus Co-Op and check the version number in the top bar. Compare it with the latest release on the GitHub releases page. If there is a newer version available, follow the update instructions above.