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edykw
User level: Level 1 (4 points)

MacBook Pro USB-C Ethernet adapter not detected after macOS 27.0.1.

Since updating to macOS 27.0.1 (Golden Gate) on my MacBook Pro (M4), my USB-C to Gigabit Ethernet adapter is detected very inconsistently. Before the update it worked every time.


Setup:

  • Adapter: USB-C to Gigabit RJ45, Realtek RTL8153 (USB vendor ID 0x0bda, product ID 0x8153)
  • Cable: Cat5e
  • Network: university residence wired network (DHCP)


What happens:

  • After I unplug and replug the adapter, the Mac sometimes takes anywhere from seconds to about half an hour to register it.
  • While it isn't detected, System Settings > Network shows "USB LAN not connected," and System Information > USB lists only the three built-in USB 3.1 Bus entries (Screenshot 1).

  • Once it registers, it appears as "USB 10/100/1000 LAN" with a 5 Gb/s link (Screenshot 2), and the internet works normally with a DHCP address.


  • The same adapter and cable work immediately with my iPhone, so the cable and wall port seem fine.


What I've tried:

  • Unplugging the adapter, the cable from the adapter, and the cable from the wall jack
  • Restarting the Mac
  • Removing and re-adding the USB LAN service in Network settings
  • Renewing the DHCP lease
  • Checking Privacy & Security > Accessories ("Allow accessories to connect")


Has anyone seen this on macOS 27, or found a fix? Is it a known issue with Realtek RTL8153 adapters? Which logs should I capture to help diagnose it?


[Edited by Moderator]

Posted on Oct 20, 2026 3:39 PM

5 replies

mkamelg
User level: Level 1 (4 points)

Oct 22, 2026 7:17 AM in response to edykw

Enter the query "usb-c to gigabit rj45 realtek rtl8153 adapter not detected macos 27 golden gate" (without the quotation marks) into the Google search engine and press the Enter key.


Depending on the version of the response, you might, among other things, be informed that Realtek has prepared an official package of drivers and diagnostic tools for wired USB network adapters:


https://www.realtek.com/download/List?cate_id=585


Description: MAC OS 11 and later (Apple ARM)

Version: 1.1.0

Update Time: 2026/09/30


The simplest way to resolve this issue is to purchase an adapter based on a different chipset. Chipsets known to be trouble-free include the Asix AX88179A (1 Gbps), Realtek RTL8156 (2.5 Gbps), and Realtek RTL8157 (5 Gbps).

edykw Author
User level: Level 1 (4 points)

Oct 23, 2026 7:03 PM in response to KiltedTim

Thanks for your reply. The manufacturer says it is a system compatibility issue related to changes in USB device identification in macOS 27.0.1. But the connection on my side has been much quicker in the past few days. So I'll let it be for now and wait for any news from them.

VikingOSX
User level: Level 10 (131,878 points)

Oct 22, 2026 8:25 AM in response to edykw

I am on macOS 27.0.1 on my M4 Mac Mini, and still running Sequoia on my 16-inch MacBook Pro M1 Pro. I recently had need for a wired Cat7 connection to my router and purchased a Cable Matters USB-C to 2.5Gb Ethernet adapter . No drivers. Connect the adapter and the operating system asks if I would like to connect it. Then it just works.

KiltedTim
User level: Level 10 (238,530 points)

Oct 20, 2026 5:32 PM in response to edykw

What did the manufacturer of the adapter say when you reported the problem to them?

edykw Author
User level: Level 1 (4 points)

Oct 23, 2026 7:05 PM in response to mkamelg

Thanks for your suggestions. I will explore these options if it gets worse again.

Originally posted at discussions.apple.com/thread/256379834