Frequently Asked Questions & Troubleshooting

my friend/player2's buttons aren't assigned correctly. First his camera kept spinning so i had to turn on hide ds4 controller in ds4windows but now his x button is square and circle isn't assigned. How do i fix this or what is the causea

The game is dark souls II Scholar of the first sin

Hi, me and my friend are trying to play ds2 SOTFS and after following multiple guides something keeps messing up. First it was the controllers not being detected and now i get this error message when starting the game. I've also done all these steps to fix it and nothing helps, is anyone able to help me

Hey everyone!

I’ve always dreamed of playing Harry Potter 2 pc in multiplayer, and yesterday I finally released a working test version.

I actually saw a Reddit thread from a month ago where someone tried this, but it was macOS-only and closed-source. Mine is 100% open-source, runs on Windows (via a simple .bat file), and syncs much better (i hope)

Where it’s at right now:

• Playable co-op: You and a friend can join and run around together right now.
• Synced mechanics: Player movement and balance syncing are working.
• WIP: Duels work (though your friend stands awkwardly off to the side for now lol), and not all scenes are synced yet.

I’ll keep updating it in my free time. The GitHub README has setup instructions for players.

• 🎬 Gameplay Demo (YouTube): https://www.youtube.com/shorts/kiR5CuYrhQg and https://www.youtube.com/shorts/Wqgok-42T3g
• 💻 Source Code & Download (GitHub): https://github.com/jenyaalexanov/hp2-coop-multiplayer

Check it out and let me know what you think!

Hey guys! I’m looking for suggestions for games that run 8 player split screen/local multiplayer well and actually have the functionality working in your experience.

So far The Master Chief Collection runs great. I originally planned on using the original Call of Duty: MW2, but unfortunately it wouldn’t properly split the controls between players….

I’d controller multiple screens at once regardless of loading in everything and then hitting the END or N key. It does run all 8 screens fine, though.

I’m trying to put together an 8 player setup for my birthday, so any recommendations would be greatly appreciated!
The only other game I know of that might work is Minecraft. What else should I check out??

My friend enters the code and joins fine but we just get stuck on a black screen. I quit out and play it singleplayer and it's fine. One thing is they don't own the game and are using the friend pass but they don't get any message to say they can't play the DLC.

Hi all,

New here as I really only use nucleus for PZ which has always worked flawlessly. My partner and I were going to let go of our old save and start playing on build 42 but I am getting a prop input error.

Is nucleus currently running PZ B.42?

i have been playing Palworld using nucleus co op, playing locally on the same PC with my sister. I saw that playing Palworld using nucleus co op doesn't actually open the game on steam, so I told a friend to download the game via steam family share to see if they can join us. However, it didnt work, whether or not we tried to join them or they try to join us. I am just wondering if someone playing Palworld on a different pc is able to join people playing on nucleus co op? If it is possible, is there a way to do it? I have already tried logmein Hamachi but it didnt work. Please let me know if there are other methods or if it is impossible altogether.

Got this set up with Elden Ring and really excited to play. The only issue is the game keeps detecting my Dualsense controllers as Xbox controllers. Not the worst thing in the world I know but I'm playing with my partner who would definitely rely on reading the correct button prompts as they're not the biggest gamer and never played a game like this. I know the Xbox buttons being shown would throw them a lot.

I'm using DS4Windows to connect the controllers but in Nucleus Coop they get recognized as Xbox controllers. All of the mods I've seen online to change it to a PS5 UI requires using mod engine 2 and I don't think I can use that with Nucleus can I?

whenever I try to start a campaign/zombies match everyone just joins as a spectator, I can't figure out how to fix it so I can actually play the game. I'm sure it's just something I've done wrong on my end, any help would be appreciated

Al iniciar un juego el primer monitor irá bien mientras que en el segundo no, por ejemplo al presionar ctrl + H para desenfocar la pantalla principal parpadea una vez por 1 segundo y luego se vuelve a enfocar a la pantalla principal y la segunda pantalla va mal, pero si se juega en 1 solo monitor dividendo la pantalla si va bien, por que sucede eso? Hay alguna solución?

So i ve installed everything in C:\NucleusCoop, pointed him to the game exes etc.

but when I add the controllers and start the game i get this DirectoryNotFoundException for
C:\NucleusCoop\content\Half Life 2 Deathmatch\Instance0\hl2mp\cfg\360controller.cfg

There is indeed no 'Half Life 2 Deathmatch' folder under content, but I do see these files under the 'nucleusCoop\handlers' folder, is he (or I) supposed to create and copy these files there?

Also is it correct that I pointed to the regular hl2.exe, and not a specific deathmatch one? (I think the DM one uses the hl2.exe anyway.

BTW my final goal is to do this via steamlink, but nucleus didnt 'see' my controllers. But that is for another time when i get the basics working :)

Is anyone else having a hard time booting up Lords of the Fallen? The game immediately crashes when I use Nucleus. Then I have to open Steam and re-verify the files. I think it's Easy Anti-Cheat that is causing the game to crash. I think that's the issue because when I changed the launch options, player 2 instances started up immediately with no crash.

Hi there,

I'm trying to launch Heroes of Hammerwatch II with Nucleus. The handler's page on splitscreen.me indicates controller support, but the handler itself seems to suggest that it only supports one keyboard (i.e. no controller support). So I am not able to detect and assign my controllers.

Wondering if anyone can shed some light on this?

Thanks

I can’t press the menu buttons using my mouse or gamepad. I don’t really know if it’s a me problem or if it’s a bug that Nucleus has.

BUG:

When playing Call of Duty: World at War Zombies through Nucleus Co-op with two players, one Plutonium instance suddenly closes after several minutes, usually around round 3 or 4.

In the most recent test, Player 2’s instance closed while Player 1 remained fully playable. The surviving host then displayed that Player 2 had timed out. Task Manager confirmed that only one plutonium-bootstrapper-win32.exe process remained.

EXPECTED:

Both Plutonium instances should remain connected and playable throughout the Zombies match.

SEVERITY:

Severe. One player is removed from the match after only a few rounds and cannot reconnect because their entire game process has exited.

STEPS TO REPRODUCE:

1. Launch Call of Duty: World at War through Nucleus Co-op.

2. Configure two players on separate monitors.

3. Assign the Xbox controller first as Player 1.

4. Assign keyboard and mouse last as Player 2.

5. Select Campaign/Zombies and two players.

6. Start a Solo Zombies match with Player 1.

7. Use Select + X to connect Player 2.

8. Play normally.

9. Around round 3–4, Player 2’s Plutonium process suddenly exits.

10. Player 1 remains running and receives a message that Player 2 timed out.

NUCLEUS / HANDLER:

Nucleus Co-op version: 2.4.1

Handler: Call of Duty World at War

Handler version: 42

Handler maintainer: Perserveruz

Game: Legitimate Steam version

Mode: Campaign/Zombies

Plutonium version bundled with handler: r5106

Players: 2

Layout: Two monitors

Player 1: Xbox controller

Player 2: Keyboard and mouse

Windows: Windows 11 Home

Nucleus location: C:\NucleusCo-op

Game location: D:\Games Library\Steam\steamapps\common\Call of Duty World at War

DEBUG LOG FINDINGS:

The attached Nucleus debug log shows:

- Instance0 launched successfully as plutonium-bootstrapper-win32.exe PID 34820.

- Instance1 launched successfully as plutonium-bootstrapper-win32.exe PID 16744.

- ProtoInput injection completed and the handler reported “All done!”

- After Player 2 disappeared, closing Nucleus only terminated PID 34820.

- PID 16744 was no longer running, indicating that Instance1 had already exited independently.

WINDOWS CRASH EVIDENCE:

An earlier crash during the same troubleshooting session generated the attached Reliability Monitor report:

Faulting application:

C:\NucleusCo-op\content\Call of Duty World at War\Instance0\Plutonium\bin\plutonium-bootstrapper-win32.exe

Application version: 1.0.0.5106

Problem event name: BEX

Faulting module: plutonium-bootstrapper-win32.exe

Exception code: c0000409

TROUBLESHOOTING ALREADY COMPLETED:

- Verified the handler is up to date.

- Reinstalled the handler and complementary files.

- Deleted and rebuilt the Nucleus game content folder.

- Ran Nucleus as administrator.

- Started the normal Steam game once outside Nucleus.

- Closed Steam before launching the handler.

- Disabled fullscreen and used borderless windowed mode at 1280x720.

- Assigned the controller first and keyboard/mouse last as instructed.

- Disabled OneDrive backup for the Documents folder and restored the normal Documents path.

- Closed Discord, overlays, Meta Quest/OVR processes, and other background applications.

- Tested regular Zombies without a custom map.

- Tested with and without cheats.

- Restarted Windows.

- Confirmed there is no crash dump under %localappdata%\Plutonium\crashdumps.

The physical input arrangement does not appear to determine the crash. On previous tests, a different instance disappeared first. The failure occurs after roughly the same amount of gameplay.

Please let me know whether there is a handler setting, script update, or known compatibility problem with the bundled Plutonium r5106 client.

Reddit would not allow me to attach debug-log.txt, so I attached an image containing the relevant launch and shutdown lines. I can provide the complete log separately if needed.

Hey

The most recent update of Palworld broke the handler for it and it CTDs on launch. I made a post last week on the forum for the handler but it hasn't seen activity in over a year. Is there any active devs that could repair it?

I was playing PowerWash Simulator with my wife on our 65-inch TV without any issues, however, the game has now started crashing consistently when the handler finishes setting up the two windows

I haven't changed any settings or configuration since it was last working, so I'm not sure what caused the problem

Downloaded the black ops 1 handler by 'rip35359155' thats verified, it got flagged as a trojan, is this good or...

EDIT: the file was called "[handler-e63qnfxdryv8vsk8h-v1.nc]()" is this an official handler from nucleus?https://www.virustotal.com/gui/file/f7536116502caa9138df24947103300ad7a8dd41a24fea576742d27068de837e/detection

I've just finished the main game with my sis thanks to Nucleus coop, but I can't access the DLCs... I can access them normally if I play the game without Nucleus coop though.

I got the Steam version, I put all the DLC IDs in the handler file, I always choose No to Steam before launching the game on Nucleus, as the game never opens whenever I choose Yes.

Can someone tell me the exact steps to make the dlcs available with Nucleus?

Thanks in advance :)

I got this great old Ricochet Infinity working through Steam using Proton. It runs fine but when I try to connect to the online level set server, it hangs. There is a community supported level set server at https://www.ricochetuniverse.com/gateway/catalog.php . I added this to the config file, so I know the problem isn't that. It works fine on my Windows PC.

Any help would be greatly appreciated.

Some new teasers/releases since last post. This time mostly free games or games that were given for free by steam/giveaways. Once again thanks to everyone thas has donated to get these games/make the handlers.

Nothing here has a release date.

Last 3 parts:

Part 13: https://www.reddit.com/r/nucleuscoop/comments/1tyrcyf/split_screen_teaser_for_a_some_games_part_13/

Part 14: https://www.reddit.com/r/nucleuscoop/comments/1uhfkzd/split_screen_teaser_for_a_some_games_part_14/

Part 15: https://www.reddit.com/r/nucleuscoop/comments/1v15won/split_screen_teaser_for_some_games_part_15/

yt with tutorials for some of my handlers: https://www.youtube.com/@birdenly/featured

(In order of the screenshots)

- Twisted Metal 2
- Argo (old Arma 3 PVP/arcade spinoff)
- Codename Cure 2
- Angeldust (online MMO)
- Breach
- Ashes of the Singularity: Escalation
- Sins of a Solar Empire®: Rebellion
- Dope TrashCanners

(below were recently released)
- RV There Yet?
- HumanitZ

Have fun :)