Quick Answer

Connect two Macs over USB using a direct USB 3.1+ cable
Requires macOS 10.15+ on both machines and Luna Display 5.3+
Auto-connects when you plug in - no manual setup needed
Apple charging cables won't work - need data-capable USB 3.1+ cables

⚙️USB Mac-to-Mac Requirements

System Requirements:

Luna Display version 5.3 or later
macOS 10.15 or later on both Primary and Secondary Mac
Compatible USB cable (see cable section below)

Compatible USB Cables

🚨 Important Cable Requirements:

Apple USB-C charging cables ARE NOT compatible - they're USB v2, we need USB v3.1+
No USB hubs, adapters, or docks - plug directly into Mac ports
USB-A to USB-A cables not supported
USB-A side must connect to Secondary Mac (Primary Mac won't support USB-A)

📱 USB-C to USB-C Cables

Use if both Macs support USB-C. Look for cables labeled USB 3.1 or 3.2 with 20Gbps+ and 4K @ 60Hz support.

💻 USB-C to USB-A Cables

Use if Primary Mac has USB-C but Secondary Mac only has USB-A.

🔌Tested Cable Options

UseBean USB-C to USB-C v3.2 - 6.6ft
USB-C 3.2 Gen2x2 Cable v3.2 - 6.6ft
Amazon Basics USB-C to USB-A 2.0 - 6ft
Truntau USB-C to USB-A 2.0 Cable - 3.3ft

🚨Note: Even recommended cables may not work in all Mac setups due to hardware differences.

🛠️ How to Connect Using USB

Step 1: Connect the Cable

Plug the USB cable directly into both Macs (no hubs or adapters)

Step 2: Connect Luna Hardware

Plug the Luna unit into your Primary Mac

Step 3: Launch Apps

Open Luna Display app on Primary Mac
Open Luna Secondary app on Secondary Mac

Step 4: Auto-Connect

If everything is compatible, Luna will connect automatically over USB

✅ How to Confirm USB Connection

On your Primary Mac, open the Luna Display app. Look in the upper right corner of Luna Settings - you'll see a cable icon with "USB" when active.

🔧 USB Connection Troubleshooting

⚠️ USB Isn't Connecting

Check Requirements:

Both Macs running macOS 10.15 or later
Using tested USB 3.1 or 3.2 cable (not Apple charging cable)
Cable supports data transfer (not charging-only)
No adapters or hubs - direct connection only

Try This Process:

Quit both Luna apps on both Macs
Plug in USB cable
Relaunch Luna apps
If no connection: restart both Macs and repeat
If still no connection: cable may not be compatible

💡 Tip: Plug USB cable in before launching apps for better detection

🚫 "Cannot Use Thunderbolt Accessory" Message

This means your cable is not compatible. Your cable likely doesn't meet the USB 3.1+ data requirements.

Troubleshooting Thunderbolt Accessory Error

😴 USB Disconnects After Sleep

After waking from sleep, Luna may reconnect over Wi-Fi instead of USB. Quit and relaunch Luna Secondary app to restore USB connection. This is a known issue being resolved in upcoming updates.