⚠️ How to Fix MU Online Crashes Due to Data Execution Prevention (DEP)

Some players may experience game crashes, errors at launch, or unexpected behavior due to Windows Data Execution Prevention (DEP) feature blocking main.exe.

DEP is designed to protect your system from malicious code but can sometimes interfere with older or heavily modded games like MU Online.

🔧 The Solution: Add MU Online to DEP Exception List

Follow these steps depending on your Windows version:

🪟 Windows 7 / 8 / 10 / 11

1. Click Start and open the Control Panel.
2. Go to System → Advanced system settings (left sidebar).
3. In the System Properties window, click the Settings button under the Performance section.
4. Navigate to the Data Execution Prevention tab.
5. Select: Turn on DEP for all programs and services except those I select.
6. Click Add… and browse to your MUOnline folder.
7. Select the main.exe file and confirm.
8. Click Apply, then OK. Restart your computer.

📝 Note: You may need administrator rights to apply this change.

💡 What If I Cant Add It?

If the Add button is grayed out or DEP settings are locked (common on some corporate or pre-configured systems):

• Open Command Prompt as Administrator.
• Run this command to disable DEP for MU Online only:
  bcdedit.exe /set {current} nx OptOut
• Then restart your PC and try adding main.exe again.

🔐 Is Turning Off DEP Safe?

You are not disabling DEP system-wide — youre just excluding MU Online from DEP checks. This is safe and recommended if youre getting errors like:

• "This application has been closed to protect your computer."
• "main.exe stopped working due to a DEP violation"

If this guide doesn’t help or youre unsure, please contact support or email [email protected].