How To Fix Modern Warfare 3 (MW3) Dev Error 6015

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Are you tired of encountering the frustrating Modern Warfare 3 (MW3) Dev Error 6015?

You’re not alone.

This error can disrupt your gaming experience, but the good news is that there are effective solutions available.

In this blog, we’ll explore practical steps to resolve the MW3 Dev Error 6015, allowing you to get back to enjoying your gaming sessions hassle-free.

How To Fix Modern Warfare 3 (MW3) Dev Error 6015?

How To Fix Modern Warfare 3 MW3 Dev Error 6015

To fix Modern Warfare 3 (MW3) dev error 6015 you can disable fullscreen optimizations, run modern warfare 3 in windowed mode, and lower graphics settings. Additionally, you can repair modern warfare 3 game files, check server status, and update graphics drivers.

1. Disable Fullscreen Optimizations

Disabling fullscreen optimizations can help resolve compatibility issues between the game and Windows 10/11’s window management features. To disable fullscreen optimizations,

  • Right-click on the MW3.exe file and select ‘Properties’.
  • Click the ‘Compatibility’ tab.
  • Check ‘Disable fullscreen optimizations’.
  • Click ‘Apply’, then ‘OK’.

2. Run Modern Warfare 3 In Windowed Mode

Sometimes, running a game in windowed mode, as opposed to fullscreen, can bypass certain errors.

To run Modern Warfare 3 in windowed mode:

  • Launch Modern Warfare 3 and access the ‘Options’ or ‘Settings’ menu.
  • Navigate to the ‘Graphics’ or ‘Display’ settings.
  • Select ‘Windowed’ or ‘Windowed (Borderless)’ from the ‘Display Mode’ options.
  • Save the changes and return to the game.

If the game is already running:

Press Alt + Enter to toggle between fullscreen and windowed mode.

3. Lower Graphics Settings

Lowering the game’s graphics settings can help if the error is related to your system’s inability to handle the game’s demands.

Reducing the resolution, texture details, and other graphics-related settings could potentially alleviate the strain on your system and prevent the error.

  • Open Modern Warfare 3.
  • Enter the ‘Options’ or ‘Settings’ menu from the main menu.
  • Select the ‘Graphics’ or ‘Video’ settings tab.
  • Adjust the following settings to lower values:
    • Set ‘Screen Resolution’ to a lower value.
    • Change ‘Texture Resolution’ to ‘Low’ or ‘Normal’.
    • Set ‘Shadow Map Resolution’ to ‘Low’.
    • Reduce ‘Particle Effects’ or similar settings.
    • Disable extra features like ‘Depth of Field’ or ‘Motion Blur’.
  • Apply the changes and close the settings menu.

4. Repair Modern Warfare 3 Game Files

Corrupted or missing game files can also cause Dev Error 6015.

If you’re on a platform like Steam, you can use the built-in options to verify the integrity of game files and repair them if necessary.

This process will check for any missing or corrupted files and replace them with the correct ones.

  • Open the Steam client and log into your account.
  • Navigate to the ‘Library’ section.
  • Right-click on ‘Call of Duty: Modern Warfare 3’ in the game list.
  • Select ‘Properties’ from the context menu.
  • In the Properties window, click the ‘Local Files’ tab.
  • Click on ‘Verify Integrity of Game Files…’.
  • Wait for Steam to validate the game files and download any necessary replacements.

5. Check Server Status

Modern Warfare 3 Server Status

Before you start troubleshooting on your end, make sure that the problem isn’t on the server side.

If the Modern Warfare 3 servers are down for maintenance or experiencing issues, you might encounter various errors, including Dev Error 6015.

You can check the current server status of COD to see if there are any notices about outages or maintenance.

6. Update Graphics Drivers

Outdated or corrupt graphics drivers can cause a multitude of issues, including Dev Errors. Make sure your graphics drivers are up to date.

For NVIDIA graphics cards:

  • Visit the NVIDIA Driver Downloads page.
  • Select your graphics card and operating system.
  • Click ‘Search’, then ‘Download’.
  • Run the installer and follow the on-screen instructions.

For AMD graphics cards:

  • Go to the AMD Drivers and Support page.
  • Select your card or use the auto-detect tool.
  • Download the driver and run the installer.

For Intel integrated graphics:

7. Run The Game As An Administrator

Sometimes, the game may require additional permissions to run properly on your system.

  • Locate the MW3.exe file in the game’s installation directory.
  • Right-click on MW3.exe.
  • Select ‘Run as administrator’ from the context menu.
  • Confirm any prompts to give the game administrative privileges.

8. Update Modern Warfare 3

Running an outdated version of the game can lead to compatibility issues and errors. Check for any available updates for Modern Warfare 3 and install them.

For Steam:

  • Open the Steam client.
  • Go to the ‘Library’ section.
  • Right-click on ‘Call of Duty: Modern Warfare 3’.
  • Click ‘Properties’, then go to the ‘Updates’ tab.
  • Ensure that ‘Always keep this game updated’ is selected.


  • Open the app.
  • Click the ‘Call of Duty: MW3’ icon on the left panel.
  • The app will automatically check for updates; if an update is available, click the ‘Update’ button.

For PlayStation:

  • Highlight the Modern Warfare 3 game icon on the main dashboard.
  • Press the ‘Options’ button on your controller.
  • Select ‘Check for Update’ from the side menu.
  • If an update is available, follow the prompts to download and install it.

For Xbox:

  • Press the Xbox button to open the guide.
  • Go to ‘My games & apps’.
  • Select ‘See all’, then ‘Games’.
  • Highlight Modern Warfare 3 and press the ‘Menu’ button.
  • Select ‘Manage game and add-ons’, then ‘Updates’.
  • If there’s an available update, it will be listed here. Select it to download and install.

9. Uninstall And Reinstall Modern Warfare 3

If none of the above solutions work, you may need to completely uninstall and then reinstall Modern Warfare 3.

This can help resolve issues caused by deeply rooted file corruption or system conflicts.

On PC via Steam:

  • Open Steam.
  • Navigate to ‘Library’.
  • Right-click ‘Call of Duty: Modern Warfare 3’.
  • Select ‘Manage’ > ‘Uninstall’.
  • Confirm by clicking ‘Delete’.
  • After uninstallation, click ‘Install’ to reinstall the game.

On PC via

  • Open the app.
  • Click ‘Call of Duty: MW3’ from the menu.
  • Click the gear icon, then ‘Uninstall’.
  • Confirm the uninstallation.
  • Click ‘Install’ to reinstall the game once removed.

On PlayStation:

  • Go to the Game Library.
  • Highlight ‘Call of Duty: Modern Warfare 3’.
  • Press the ‘Options’ button and select ‘Delete’.
  • Confirm to uninstall.
  • Re-download the game from your Game Library or the PlayStation Store.

On Xbox:

  • Press the Xbox button and go to ‘My games & apps’.
  • Select ‘Games’.
  • Highlight ‘Call of Duty: Modern Warfare 3’.
  • Press the ‘Menu’ button and select ‘Uninstall’.
  • Confirm to uninstall.
  • Reinstall from ‘My games & apps’ under ‘Ready to install’ or the Xbox Store.

10. Contact Modern Warfare 3 Customer Support

Modern Warfare III Official Support 1

If all else fails, reaching out to Activision’s customer support for Modern Warfare 3 can provide you with additional assistance and potentially more tailored solutions for the Dev Error 6015.