ARC Raiders Launch Error Maximum Simultaneous Game Instances Reached

This error usually happens because Easy Anti-Cheat (EAC) thinks ARC Raiders is already running in the background, even though you can’t see the window.

It is a “ghost process” issue common with Embark Studios games (like The Finals).

Here is the step-by-step fix to clear the stuck instance:

1. The Quick Fix (Task Manager)

• Press Ctrl + Shift + Esc to open Task Manager.

• Look for any of the following processes:

  • ARC Raiders

  • Discovery (The internal project name often used in the process list)

  • EasyAntiCheat_EOS

• Right-click them and select End Task.

• Important: Also check the “Details” tab if you don’t see them in the main list.

2. The “Stuck Driver” Fix (If Task Manager fails)

If you can’t find the process or it refuses to close, the anti-cheat driver is likely stuck at the kernel level.

• Restart your PC.

• Do not just put it to sleep; do a full “Restart” from the Start Menu.

• This is often the only way to unload a frozen EAC driver.

Also read : Service Instances Unavailable Roblox Error Code 9007

3. The “Corrupted File” Fix (If it keeps happening)

If the error comes back every time you launch:

1. Navigate to: C:\Program Files (x86)\EasyAntiCheat_EOS

2. Find the file: EasyAntiCheat_EOS.sys (It might just say “EasyAntiCheat_EOS” if you have file extensions hidden).

3. Delete this file.

4. Launch ARC Raiders normally.

   • Result: The game will detect the missing file and force a clean reinstall of the anti-cheat service, which usually fixes the “simultaneous instances” bug.

4. Check Conflicting Games

You cannot run two Easy Anti-Cheat games at once. Ensure you have fully closed:

• The Finals

• Fortnite

• Apex Legends

• Elden Ring

Verify Files on Steam

Here are the steps to verify the integrity of game files on Steam. This is the official way to force the game to repair itself without redownloading the whole thing.

How to Verify Files on Steam

1. Open your Steam Library.

2. Right-click on ARC Raiders in the list on the left.

3. Select Properties… from the menu.

4. Go to the Installed Files tab (sometimes called “Local Files”).

5. Click the button that says “Verify integrity of game files”.

• What happens next: Steam will scan every file in your game folder. If it finds any file (like the anti-cheat driver) that is broken, missing, or “stuck,” it will automatically re-download just that specific file.

• Time: This usually takes 2–5 minutes.

If Verification Doesn’t Fix It (Advanced Steps)

Since this specific “Maximum Instances” error is caused by a “zombie” process that refuses to close, here are two more aggressive fixes confirmed by the community:

1. The “True” Restart (Fast Boot Issue)

Windows 10/11 has a feature called “Fast Boot” that saves the kernel state even when you shut down. This means the stuck anti-cheat driver stays stuck.

• Fix: Do not just press the power button. You must click Start $\rightarrow$ Power $\rightarrow$ Restart. This forces a complete kernel flush.

2. The “Nuclear” Anti-Cheat Reset

If the error persists after a restart, the anti-cheat service is likely corrupted.

1. Go to this folder on your PC:C:\Program Files (x86)\EasyAntiCheat_EOS

2. Delete the entire folder.

3. Go back to Steam and run the Verify Integrity steps above.

   • Result: Steam will see the folder is missing and download a fresh, uncorrupted version of the anti-cheat.