macOS 27 Golden Gate - Ethernet connection broken, missing Local Network permission

LightBurn Software Questions OS Specific
,
1

Problem:
After upgrading to macOS 27 Golden Gate, LightBurn can no longer connect to my laser over ethernet. The device cannot be found despite the IP address being correct and unchanged.

The root cause appears to be macOS 27’s Local Network permission enforcement. LightBurn does not appear in System Settings > Privacy & Security > Local Network, and never triggers the permission prompt on launch or connection attempt. Without appearing in that list, macOS silently blocks all local network UDP traffic from the app.

This is a known issue affecting Qt-based applications on Golden Gate — the Qt networking layer does not correctly register with macOS 27’s local network permission system, so the prompt never fires and the app never gets access.

Workaround currently used: Saving .rd files to USB stick and running from the controller directly.

Request: Please investigate Golden Gate compatibility for ethernet connections and coordinate with Qt if a framework update is needed to correctly trigger the local network permission prompt.

2

Hello Jerry

Reporting internally but a couple questions

With LightBurn closed - if you open a terminal and do

ping
arp -a
nc -vz 50200

Are you able to successfully get replies from the laser?

3

Thanks for the reply

Update with diagnostics:

Ran the suggested Terminal commands with the following results:

ping 192.168.1.199 — successful

arp -a — laser controller visible at 192.168.1.199, MAC address confirmed

nc -vz 192.168.1.199 50200 (TCP) — connection refused (expected for UDP device)

nc -vzu 192.168.1.199 50200 (UDP) — succeeded

This confirms the network path to the controller is completely open. The Mac can reach the laser on exactly the port LightBurn uses when accessing it from Terminal, which runs with elevated privileges that bypass macOS 27’s local network permission check.

The problem is definitively inside Golden Gate’s local network permission enforcement. LightBurn never appears in System Settings > Privacy & Security > Local Network, never triggers the permission prompt, and macOS silently blocks its UDP traffic as a result. Terminal bypasses this restriction, which is why nc -vzu succeeds while LightBurn cannot find the device.

This is consistent with a known issue affecting Qt-based applications on macOS 27 Golden Gate where the local network permission prompt is never triggered and the app never gets access.

Is there a workaround or fix in progress?

4

Hi Jerry,

Sending you a private message.

5

Ran into this today when setting up my first laser - bogged me down a good bit. ChatGPT got me past it by suggesting to open my full home subnet to private networking for all apps. Worked for me (run this in Terminal, if you decide it is ok for your machine security, replacing my example subnet with your proper one):

sudo defaults write com.apple.network.local-network AllowedEthernetLocalNetworkAddresses -array “192.168.1.0/24”

sudo defaults write com.apple.network.local-network AllowedWiFiLocalNetworkAddresses -array “192.168.1.0/24”

6

I was pretty excited by the prospect of a true bypass, but alas, it didn’t work for my issue. Thanks so much for sharing your experience and solution. I will certainly do the same, should I find a workaround. Currently, I’m having to dump the projects out to a USB drive. Not super convenient, but at least I can get some things done.