The original post is from OnlineTechTips. Credit for them.
Is your Windows keep popping-out the "USB device not recognized" one day when you plugged in your thumb drive or whatever USB device? Even tried to repair registry, repair driver, reformat and the problem still persists? Suspecting the motherboard USB ports had spoilt? Take it easy, there is still something for you to try before you pulling all you hair out and bang your head to the wall. Here I quote the whole article from OnlineTechTips:
Are you getting a “USB device not recognized” error whenever you plug in a USB mouse, keyboard, or other USB device? I love USB and have 5 ports on my computer so that I can connect my mouse, keyboard, camera, phone, and printer to it all at once!
However, last weekend, my computer stopped recognizing my USB devices! The strange thing about it was that the USB ports were not bad because all of my devices were still getting power to them. I could still charge my cell phone without a problem!
So I started with the normal fixing methods, including uninstalling the drivers for my devices and reinstalling them. That didn’t work! Next I tried System Restore thinking that maybe I had installed something and it caused a conflict with the USB system drivers. That didn’t work!
I read online that in order to fix this problem I should go to Device Manager and uninstall all of the devices under USB Controllers. Restarted the computer, reinstalled the USB drivers, but the problem STILL did not go away!
You may also see in Device Manager that the device shows up as an “Unknown Device”.
So how did I finally fix the problem? Well, apparently it’s a super simple solution! No need to edit the registry, uninstall drivers, or anything of that sort.
Simply UNPLUG YOUR COMPUTER FROM THE POWER SUPPLY. Yes that’s it! Note that this does not mean just turning off your computer because modern computers don’t really turn off when you press the power button as the motherboard still gets power.
First to explain, the motherboard is where all of hardware of the computer is connected to, including the USB ports. Sometimes the motherboard needs to be “rebooted” also because something can go wrong, i.e. all your USB ports suddenly stop working. The small microprocessor on the motherboard will reload the drivers and your USB ports should be back to recognizing all devices!
So first turn off your computer using Shut Down or pressing the power button and then UNPLUG it from the wall outlet. Let it sit for about a minute and then plug it back in.
Hope this helps someone fix that pesky “USB device not recognized” Windows error!
So there you go, unplug your pc from the power point and see if the problem solved. This solution has helped many happy users to solve their problem, hope it helps you too!
Techie Talkz 
To whom posted the solution how to solve device nor recognized.
I tried what you posted but in my case it did not work. I had an IPod mp3 player that I can not make any of my computers to recognize it. (have 3pc)
Mr yagala Thanks I’ll try your solution
Hey!
I’ve tried this and almost every other thing I could possibly think of.
I have a USB device that is made to plug in a PS2/PSOne controller to your PC. This device has been working for several years and when I installed windows 7 the first time it was a lil problem to get it working but it did. Then all of a sudden one day I had had it unplugged for a week or so and when I pluged it in I got the message “USB Device Not Recognized”. Problem is that for the device to work it needs to be recognized as a HID Compliant Device but it simply refuses. I’ve tried every ordinary step to have it up and running but when I get to the final steps it always comes back to “Unknown Device”(USB).
Any ideas??
If you really did everything that I posted, including the alternative solution one, I would suggest you to try your PlayStation controller converter in other computer. This is able to try out whether is it the converter itself having problem. And also if the USB ports that you tried on with your converter are workable with other devices, most likely your converter is spoiled (not 100% sure though, hardware is non-predictable).
Hope you able to find out the root of cause!
GHOST301
YES THANK YOU, it worked when i unplugged my battery from laptop, my computer had start recognised my devices :- )
best regards
You’re welcome! Glad I had helped you 🙂
You’re a life-saver, man! I was almost going out of my mind.
I began to have the situation this morning (Sunday Nov 22). I tried everything I know and others I read online, yet, nothing. I use a hp dv4 Pavillion, so, the problem also affected the finger-print reader apart from the USB ports/devices.
Thank you for that very important piece of information. I sincerely, truly do appreciate. Thanks!
No problem mate, glad my article is able to help you …
Cheers,
Taylor
this never worked
the problem is not my laptop bt the usb device
Hi there,
If the problem lies on the USB device, obviously my stated solutions will not work for you. It’s only used to solve Windows conflict with USB ports. Sorry that I can’t help you much.
Rgds,
Taylor
Thanks so much for this!!!
This seems to have solved my problem…I agree with one of the comments to also remove the battery (if you’re using a laptop/notebook) when you “unplug your computer from the power supply.”
Fixed an annoying and very perplexing problem…thanks so much!
Regards,
Dave
No problem Dave, Glad you have your problem solved. 🙂
Rgds,
Taylor
Hi There,
This is vishal overhere. actually i went through your article about UNPLUG YOUR COMPUTER FROM THE POWER SUPPLY then try it……………..
but still i am not able to connect my ipod with my computer…………..i have ipod classic80gb……….. so dear can u please tell me some other way…..
Hi Vishal,
Have you checked the other post of mine for the possible alternative solution? https://ghost301tech.wordpress.com/2009/10/04/how-to-solve-usb-device-not-recognized-problem-in-microsoft-windows-alternative-solution/
Rgds,
Taylor
oh my god it worked for me 🙂
that was so simple, i started to panic thinking i had to spend money getting it repaired 🙂
This works for me, as it did for most people. But my laptop goes back to giving me the same ‘not recognized’ message on the next boot. So then I have to power down, unplug, wait, power on, reset time & date, before I can use my flash drives. It seems that the ‘fix’ is only good for one boot. Is there any way to fix this dreadful problem in a more permanent way?
Hi Daren,
I am not sure but it is possible that your USB ports have physical damage, or the power management of the USB isn’t set correctly. I would suggest you have your laptop checked by the manufacturer to find whether there is problems with your USB ports.
Rgds,
Taylor
I have windows 7, and unplugging my power supply and restarting did nothing.
In My Computer i got the following error “Disconnect the Digital Still Camera from its current port and then connect it to one of the ports on a hub shown in bold type”. Pls solve me anybody on step by step
Hi,
As the message shown, you have to connect your digital camera to the other favored hub (from what I read from the message). Can you try connect your digital camera to other USB port when this message appear?
Rgds,
Taylor
hi mr.ghost301
im francis from the philippines i haave a problem on my usb drive first the problem is my usb flash drive note recognize and the other day it doenst detect in my computer or even in other internetcafe how can i fix if it no longer been detect and even the message when i plug inmy usb the not recognize it doesnt show now i go to device manager the problemm is 2 usb ports have a problem how can i fix it!!!
pls help me mr.ghost301 i have my all files on my usb and my thesis save on my usb drive!!!!
thank you!!
and good day!!!
Hi Francis,
I am sorry to hear that. If you tried your USB drive to the other computer but still remain the same problem, most probably your flash drive is broken. Probably you can look for the shop that provides data recovery from your USD flash drive, if it is really necessary.
Rgds,
Taylor
gud day sir
ok tnx sir i open it its broken hmmf after i goto shop to repare it can i retrive my files and can i use again my flash drive sir!! . . .how can i fix f my usb is problem looks like in the image on the top of the unknown device how can i fix it sir!!!
thank you!!!
Hi,
thanks for ur help BUT the problem in my External HDD when I plug in to any PC or laptop it give me same error USB device not recognized !!
by ur step I fixed it and working back but the problem I should to do this every time I need to open it?!?!! it very hard and not make sense please any help ??
Hi,
I suppose this issue won’t always happen, but if it does, I am afraid you have to do that every time. Is it possible that your external HDD already having some issue? Just guessing.
Rgds,
Taylor
i tried the same method but the problem is still resisting
Hi,
If the problem still persists, I think it would be either the USB device is already malfunctioned or the USB port of your motherboard is already malfunctioned.
Rgds,
Taylor