I have a plain MacBook. When I use it in my office, I connect it to an Acer display. Most mornings, I use the MacBook away from the Acer display, and then connect it when I return to my office. At this point, sometimes ethernet works, and sometimes it doesn’t. That’s the problem, and it has been recurring since I bought the Acer display in 2016.
Ethernet comes from an Apple Time Capsule, through an ethernet to USB adapter. (I have three of them from two different manufacturers; the problem is independent of the adapters.) The ethernet adapter is connected to one of the Acer display’s two USB ports. My primary guide that ethernet does not work is that the indicator in the Network pane remains red, but that indicator seems to completely reliable regarding the status of the ethernet connection.
The MacBook is running MacOS X El Capitan 10.11.6. (There might have been an incremental update since I bought the Acer display; I don’t recall.) Anker (manufacturer of two of the ethernet adapters) support suggested I install the latest ethernet drivers, which I did.
When the Acer display was new, ethernet rarely worked upon reconnecting the Acer display. After installing the new drivers made no difference, Anker sent a replacement ethernet adapter, which made no difference. For some reason lost in the mists of time, one day I connected the ethernet adapter directly to the MacBook when I returned to my office, and the indicator in the Network pane turned green. After the MacBook went to sleep, I disconnected the ethernet adapter, connected the MacBook to the Acer display, woke the MacBook, and found the Network indicator was green. I thought I had found the solution, but I was wrong.
Since then, I have tried waking the MacBook and connecting ethernet before using the MacBook remotely and then connecting ethernet after return and letting the MacBook fall asleep before connecting it to the Acer display. I have simply taken the MacBook for remote use but then connected ethernet directly when I returned to my office. I have simply taken the MacBook, used it remotely, and connected the Acer display when I returned. (That’s the procedure that failed almost all the time when the Acer display was new.) All of these usually work, but fail with distressing regularity.
These days, when ethernet does not work, I restart the MacBook and then ethernet works. (At least once, that did not solve the problem, but a subsequent restart did.) Many months ago, I simply used the MacBook without ethernet, and ethernet started working when I woke the MacBook. (Sometimes it seemed to require four hours; sometimes it seemed to require two days. I have no idea why it was different.)
Does anyone have any hints on improving the reliability of establishing an ethernet connection? For that matter, does anyone have a similar setup, with or without the ethernet problems? Thanks for any help.