Wednesday, March 16, 2011

"Network Cable Unplugged", but it isn't!

Today morning, when I sat down at my desk and opened the browser to check my mails, I found that my computer was not connected to the internet. I ran the Win 7 trouble-shooter to diagnose the problem. It said "Network Cable Unplugged". I was like "What the...?" I quickly turned over the cabinet to see where the ethernet cable had run off. It was sitting well behaved in its slot. Then what was causing Win 7 to say that the network cable was unplugged?

I checked the socket connection on my wall to see if the other end of the cable had been disturbed. It was also tightly lodged into its socket. I asked Win 7 for a detailed description of the problem and this is all it could say, "Network cable Unplugged or Broken". Wow, that was descriptive! At least it gave me something new to work with. I replaced the ethernet cable to see if the original cable had any loose-connections in it. Unfortunately, the new cable was also of not much help. The same "error" kept occurring.

Well, if the ethernet cable was not faulty, then was the wall socket faulty? I tested that by connecting the cable to another free slot and still Win 7 said, "Network Cable Unplugged". But it wasn't! Like any other trouble-shooter, I resorted to restarting my machine, and checked if that helped. No, it didn't.

Suspicious that it might be a Windows related problem, I booted into Ubuntu to check if the same problem persisted over there. Not so surprisingly, I was able to connect to the internet without any problems. So, at least the problem was narrowed down to its source. Buggy WINDOWS 7.

Now that I had the power of the internet, I plunged into the World Wide Web to find a solution for this "problem". Not many articles talked about this problem. The few of them that did were happy to stay working with Ubuntu. Sadly, I could not do that. Some of the applications that I require, do not run on Ubuntu, or at least, requires a lot of work to make them run on the Linux flavour. Finally, I came across a forum with a user who had faced the same problem. His "solution" to rectify the problem is given below.

1. Shut down your PC.

2. Unplug the power cord.

3. If you have a laptop, remove the battery as well.

4. Walk away from the problem for at least 30 minutes.

5. When you return, reconnect battery and power cord.

6. Start as usual.

7. If this solves the problem, take 20 minutes and post this to all of those message boards that you didn't find the solution to.

I seriously laughed aloud at the above set of "instructions". What else do you expect a computer science engineer, researching in computer science, to do, when he/she reads such instructions? The instructions looked ridiculously stupid and not worth trying. Therefore, I spent 30 more minutes searching for "proper" instructions to solve the problem. Sadly, I didn't find any. I was seriously frustrated at this point. So, I thought, "well, there is nothing to lose in trying out the above instructions", and gave it a shot.

I shut down my PC and unplugged the cord. My PC is a desktop machine so point #3 does not apply. I also walked away from the problem (it was lunch time and I was feeling hungry). When I returned (35 minutes since I left, to be precise), I connected the power cord and started the machine.

Well, I guess all of you have already expected what the outcome was going to be. Let me swallow my pride and tell you, the bloody thing worked! I was able to connect to the internet in Windows 7. I was lost for words when the minimalist Google page loaded when I opened my Chrome browser. I was literally scratching my head wondering what shutting down the PC for 35 minutes could have done that restarting didn't.

The only logical solution that I can come up with is that, shutting down the PC and unplugging the cord from the socket would have earthed some stray eddy currents that had accumulated on the chipset. I cannot think of anything else. MS needs to look into their network drivers and try to make it more robust to eddy currents.

Finally, since the instructions worked, I could not help but follow the final instruction in the list. I have taken 45 minutes to compile this blog post in hope that it will help someone else with the same problem.

P.S. If anyone else has any logical reason for the above solution, please leave them in the comments section.


Amiya Patanaik said...

Wow that was really weird.....I am not aware of any memory component that retains data for 30 mins!! So the stray eddy currents logic sounds good...

Adithya said...

Hey Vittal, it happened alot of time in Grad Hall for me. The above solution works like a charm.

Vittal P said...

Cool. Glad that it helped. I heard you need to unplug for just a couple of minutes. That will remove the static from your motherboard.

Ajay said...

W.I.E.R.D! But to be frank, I wouldnt think it was eddy currents, the last I heard, those things just last microsecs. I would also be surprised if the guys working in Linnux drivers took currents into the equation when they did their designing...I would not really be surprised if this was faulty Windows drivers at work :). try System Restore next time this happens and lemme knw the result...But really really wierd. Would pay to knw the what the culprit really is!

Vittal P said...

@Ajay: The 30 minute thing was a joke. Looks like all that is required is for you to unplug and press the power button. That will earth the stray eddy currents on your chipset. You don't need to wait for 30 mins or so. Just a couple of seconds would be enough.

Moreover, I don't think the Linux drivers are also designed to take into consideration these stray eddy currents. I just feel their approach and algorithms are much more advanced and intelligent to neglect such minute aberrations.

Ivan Ferrer said...

Good article.
But I tried the same power-off solution with no luck. My lan alternates connection-disconnecion every 3 seconds, and Windows shows that 'Network cable unplugged' error.
BUT I found another solution not less 'stupid' that also worked like a charm:
My ethernet cable (RJ45 connectors) is like 15 meters long, and at some point it has a two-female conector to extend it. At that point it is surrounded by several electric and telephone cables. Somewhere I read that those cables can create interferences to network cables.
I moved that connector like 50cm aside and ¡voila!: perfect connection.
ps:Im sorry, I dont have an appropiate blog to post it :)

cheyann said...

This one works so well. Is it fine to share your tips to
Networking cable Online Shop in UK?

Mark said...

Brilliant! That worked. I had spent about two hours troubleshooting when I found your page. I unplugged the power cable for about 5 minutes, plugged it back in, and the NIC came to life! My NIC went absent after installing a new drive in the system. I used my anti static strap as usual, so who knows what happened. The whacky thing is Windows device manager was telling me the device was working properly, so they do have some issues there. Thank you.

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Audrius Butkus said...

I have pretty strange problam:
1) My windows 7 network icon on right bottom side shows that my cable is unplugged.
2) my internet works. (as I am posting now, icon stil lshows my cable is unplugged)
3) maybe there is some kind of bug of that in windows 7.
4) some people may noit even try to start browser to see if internet works if they see that kind of icon.

try it, maybe internet just works, and bug only on icon.

sdsd said...

Man, this really works, I took out the battery for 20ish minutes and BOOM it was back to working again. Really hard to believe but it sure worked for me. Thanks a lot!!!