Surface Pro 4 Dock Ethernet connectivity problems

I have similar problem: good ethernet cable works on all laptops it's plugged into, but on the dock, it consistently says "Network cable is unplugged"

Microsoft is sending me a replacement so we'll see if they fixed it, but odd that they didn't try to troubleshoot the problem and told me to keep the old one.

Very similar story here.  I have a Surface Pro 3 with a Docking Station (frame you put it in). The LAN port worked fine until a Win 10 update sometime in Oct (from memory). After the update, no LAN port (cable unplugged)...

My system eventually succumbed to the Windows Update onslaught and had to be reimaged.  After that, still no LAN port.

I then got a Surface Pro 4 with Windows 10 (I'm a slow learner) and a Dock (the brick).  The LAN port on this never worked.

I have checked my LAN setup and the cables and they all work fine with other systems.  My feeling is it is a Surface Pro/Windows 10 issue, not a Dock issue.  I find it significant that it all went to pooh just after a Windows 10 update.

Similar issues with my SP4 and Surface Dock (the new version).

Half the time the connection states unplugged.  When I finally get a connection it is up for a moment, then down, then up... Repeat. 

My Surface USB Ethernet Adapter works perfectly, no issues at all.

Haven't found a solution.

New SP4 i7 purchased from MS Store.  Surface dock purchased from BestBuy.  Wired connection just shows "cable unplugged".  Replaced dock still have same issue.  Yes, did the requisite troubleshooting and everything functions without the surface.  I even purchased a USB Ethernet connection cable from Microsoft with the same result.

Okay, 2500 bucks to Microsoft and there is a defect.  I understand that.  What floors me is the support I received from Microsoft.  Absolutely deplorable.  When I finally was able to escalate this issue I was told to send the machine back for replacement or refund.

Now this surely seems like a driver issue to me however the "techs" at Microsoft wanted me to reboot and try again several dozens of times.  Basically clueless outside of the script.

I am sorely disappointed at the support and complete lack of concern of my issue.  "Just return the Surface Pro4 then, that is your only option".  Well, no it is not.  I would consider doing it IF they would tell me that it is a known issue.  But returning the machine (which I use for work), waiting for a new one, and finding the same issue would not be good for anyone.

Hey Microsoft,  I supported you for 30 years as a developer and one of the first Gold Partners.  Not a dollar more will I spend with the "store" or on anything for which I can get an alternative.

Shame on you Microsoft.

And, still no updates for SP4.

I see the 1/21 "Announcement" above but only pertains to SP3.

SP4 still running with 12/17/2015 updates.

Hope Microsoft gets around to fixing the Ethernet on its Surface Docks!

In the meantime, my Surface Dock is going back to Microsoft for refund.

I have had a bit of a breakthrough with this.  My current network uses Cat 5e cabling but runs 1000Mbs.  I know this is not the most reliable combination but it has always worked fine until now.  Also I make my own cables (and test them!!).

The installed LAN cabling uses just the prescribed RJ45 Ethernet wires with the rest not connected. This should work fine for Ethernet and has up until this problem surfaced.

Following up on a bright idea, I went out and bought a 10m LAN cable. Couldn't get Cat 5e so ended up with a (fully compatible) Cat 6 cable (a bought one). I then connected it directly to the switch, bypassing my installed network cables and, **** down, it worked.  I am now using my LAN port on the Docking Station for the first time in three+ months.

I will now go through the combinations and find out what configurations work and what don't and report back here with the results.

Third attempt at a Surface Dock was finally a charm.

Key for me seemed to be Lot Numbers.

My 2nd Surface Dock (detailed above Jan 2016, still with faulty wired Ethernet connectivity issues) was Lot No. 1544.  That was returned to Microsoft Store.  Don't recall exact Lot No. on my 1st Surface Dock (which was also returned) but it was definitely a smaller number than 1544.

My 3rd Surface Dock, purchased Feb 2016, is Lot No. 1547.  This one seems to be good.  Ethernet works well.  Able to keep power to the Dock with long periods (> 1 week) of wired Ethernet stability.

So my advice to the community is to beware of wired Ethernet misbehavior in early lots of Surface Docks, prior to Lot No. 1547.  If you're purchasing a new Surface Dock, make sure that the Lot No. is 1547 or greater.  (You can find the Lot No. in very small print on the bar code label that contains the serial number and model number.)

I had the same problem :

- I couldn't have the Surface with the wired Ethernet in my office desk.

- A "tradionnal" laptop work fine with the wired Ethernet in my office desk.

- The Surface 4 work fine directly pluged to the switch. 

My solution to have the Surface 4 with a wired Ethernet in my office desk : force the port of the switch to 100Mbs ... 

[Sorry for my broken English]

The lot number did the trick.  1549 works great.  Finally.  Thanks EricST01.