1. Open Second Display on both Macs. The display Mac says “Waiting for your Mac…”.

  2. Make sure both Macs are awake.

  3. Use the same cable or network for both Macs: a cable between them, or the same Wi‑Fi or Ethernet network.

  4. On macOS 15 or later, allow Local Network access for Second Display on both Macs. Allow Local Network access

  5. If Second Display mentions a charging cable or Thunderbolt Bridge, follow its message. The cable messages

  6. Click Try Again, or turn the display’s switch in the menu off and on.

If the display Mac says “Other Macs can’t see this Mac. Restart Second Display if it keeps happening.”, quit Second Display there and open it again.