System Extension Blocked Error on Mac: How to Fix

If you're seeing messages like "System Extension Blocked", "iCoreService would like to use a new endpoint security extension", or "iCoreService would like to use a new network extension" on your Mac, this guide is for you. Follow these steps to enable Trend Micro Antivirus extensions and keep your Mac protected.

Why am I seeing these error messages?

These messages appear because Trend Micro Antivirus needs system extensions to provide complete protection for your Mac. These extensions require specific permissions to operate effectively without needing kernel-level access.

How to Allow Trend Micro Extensions on Your Mac

Follow these steps to permit Trend Micro Antivirus extensions based on your macOS version:

For macOS 15 Sequoia

1. Click on Open System Settings from the popup.
2. Navigate to 'Login Items & Extensions'. Scroll to Extensions > Endpoint Security Extensions, and click the (i) button.
3. Activate the Trend Micro Antivirus Extension by toggling it to ON.
4. Enter your Mac username and password, click OK, then click Done.
5. Again, click Open System Settings from the popup.
6. Go to Login Items & Extensions. Scroll to Extensions > Network Extensions, and click the (i) button.
7. Activate the Trend Micro Antivirus Extension by toggling it to ON.
8. Enter your credentials once more, click OK, and then click Allow when prompted.

For macOS 13 Ventura and macOS 14 Sonoma

1. Click on Open System Settings from the popup.
2. In the Privacy & Security section, scroll to Security and click Details...
3. Unlock settings: Enter your Mac username and password, then click Unlock to allow changes.
4. Select and enable all Trend Micro Antivirus Extension items, then click OK.
5. When prompted, click Allow to finalize the permissions.

For macOS 12 Monterey and older versions

1. Click OK on the popup to start.
2. In the 'Permission Overview page', select Continue.
3. Open System Preferences by selecting the corresponding button.
4. Unlock the settings page by clicking the lock icon.
5. Choose Allow next to the Trend Micro entry.
6. Select Placeholder Developer from the list, then click OK.
7. When you see another popup, click Allow again.
8. Notice the changes on the page and click Continue.
9. Reopen System Preferences by selecting the button again.
10. If the settings page is locked, unlock it again.
11. Go to Full Disk Access, and check both Trend Micro Antivirus and the Trend Micro Antivirus Extension.
12. Finally, click Verify to ensure all permissions are set correctly.