This happens when XInput IDs clash. Ensure you launch Nucleus Co-Op as an administrator. If the issue persists, open the Nucleus settings and enable "Hook Focus" or "Hide Cursor" to prevent input bleed-through. Issue 2: Second Instance Fails to Join the LAN Lobby
On Instance 2 (Player 2), navigate to and look for available matches. Player 1's lobby should appear in the local server browser.
Extract the contents of the zip file into a dedicated folder (e.g., C:\NucleusCoop ). extract it into your game directory or Program Files, as Windows permissions can block it.
Once both instances are loaded on your screen, navigate to the menu on Player 1's screen. Select LAN Party or Local mode.
To play split-screen Zombies in Call of Duty: Black Ops 1 on PC, you must use a third-party tool like Nucleus Co-op , as the native PC version lacks built-in split-screen support.
The tool will automatically open two separate windows of Black Ops 1, resize them to fit your split arrangement, and assign your controllers.
Navigate to your Black Ops 1 installation folder and select BlackOps.exe .
Click to let the tool scan your drives, or click Add Game to find it manually.
However, for years, PC players have faced a frustrating reality: unlike its console counterparts (Xbox 360 and PS3), the native PC version of Black Ops 1 . The option is buried, disabled, or simply non-existent in the standard menu.
Call of Duty: Black Ops 1 Zombies remains a high-water mark for the franchise. Maps like Kino der Toten, Five, and the DLC classics offer endless hours of cooperative survival.