USB Hard Drive not Recognised in Windows 7 (Code 43) - Solution

Setting the Scene

This is my account of what I did to fix the “USB Device not recognised” error in Windows 7 (Code 43) when it happened while I was using an external hard-drive (with its own power supply). If you are of an impatient disposition and want to know what worked for me, without reading the entire article, you can scroll down to the section entitled ‘My Fix’.

I purchased a 2TB external hard-drive for my desktop PC in order to free up the space being used to store photographs, audio files and video files. I proceeded to transfer the files from the internal drive to external one, checking that the transfer was successful as I went, and when I was finished I shut the computer down for the night.

USB Device Not Recognised
USB Device Not Recognised

An Unforeseen Event

When I switched the computer on again the next morning, Windows 7 informed me that the “USB Device [is] Not Recognized” and when I had a look for it in Windows Explorer it (and all of my files) was nowhere to be found! I checked Device Manager and saw the dreaded yellow ‘!’ beside “Unknown Device” and panic quickly set in; under the properties for the "Unknown Device" the status read:

"Windows has stopped this device because it has reported problems. (Code 43)"

Could things get any worse?

“To the internet” I declared, and began my search for a solution.

Unknown Device
Unknown Device

Hours spent forum hopping only served to panic me further. I had visions of all of my files being … gone, due to getting a faulty drive (I KNOW I should have backup). It was horrible. I began systematically implementing every suggestion I could find that looked like it had half a chance of working: chipset up to date, check; uninstall/reinstall USB controllers, check; working in another USB port? No, all the same; works in another computer, yes (at least my files are safe!); works in another Windows 7 computer, yes again; power off computer and disconnect from mains, same problem – no fix.

Windows has stopped this device because in has reported problems. (Code 43)
Windows has stopped this device because in has reported problems. (Code 43)

My Fix

I then read about a problem that Windows 7 sometimes has when waking devices from a sleep state; surely it couldn’t be that simple. I connected the drive to my computer by the original USB port, reached behind the drive and plugged out the power connection, counted “One Mississippi, two Mississippi, three … “ to ten and plugged it back in. "Ta-dah!" Windows 7 recognises the drive, loads the drivers and presents me with all of my files. Phew!


Hindsight is said to be one of mans greatest gifts; so you don't have to use yours, here's the list of possible actions to take in order of ease:

  • Do what I did; unplug the external hard drive and after a few seconds plug it in again.
  • Try using the USB device with another USB port; if it works fine in another port the original port may have malfunctioned.
  • Shutdown the computer and disconnect it from the power so that all charge has dissipated from the motherboard. In the case of a laptop, removing the battery does the same thing.
  • Try using the USB device with another computer; if it works in another computer you know the problem is with the original.
  • If both computers have the same operating system and it works in one and not the other the problem would more likely to be a hardware one.
  • If the computer’s operating systems are different and it works in one it may be a compatibility problem with one of them. It could still be a hardware problem though.
  • Uninstall all USB controllers in Device Manager and restart the system. This will allow Windows to reinstall all of the USB controllers.
  • Make sure that the drivers for the BIOS and motherboard are up to date.
  • Restore the operating system to a point where everything was working okay.

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Comments 28 comments

rt 5 years ago

you are a genius!!!!!!!!!!!!!!!!!!!!!!!!!!!!! after looking for a fix for hours you are the only one that fixed my problem in a matter of ten seconds in such a simple way. thank you!!!!!!!!!!!!!!!!!!!

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Barraoc 5 years ago from Co. Meath, Ireland Author

Glad I could help @rt

Raymond 5 years ago

Wow ... dude!! you saved my consulting practive

asbestos 5 years ago

Thank you!

Microsoft support don't help me, but you (:

James 5 years ago

Do you think the fact I got the exact same error except in two windows 7 machines, and it coincided with my hard drive inexplicably falling to the ground (3 foot fall onto carpe) means that it is FUBAR?

Daniel 5 years ago


Worked great. You saved my day!

deepshikha gupta 5 years ago

it happened with my pendrive and its not working with any other laptop too..plz tell me what should i do?

Mike 4 years ago

I read your article and immediately determined you were an idiot before even testing your solution. I had tried a number of various unplugging and plugging techniques to no avail. I had also tried a number of 'recovery' and 'detection' programs and even tried to re-assign the drive letter (didn't work because it wouldn't recognize the drive at all) and found no solution. There was NO WAY i had not already tried your solution.....or so I thought.

So i figured that in reality, i was the idiot because i unplugged my external hard drive before it was finished because it seemed to have frozen my computer. So I tried your solution and it actually worked. I was excited and pissed off at the same time. I was glad to have my data back (pictures of my kids) but i was mad that i wasted 4 hours only to find the solution was so stupidly simple.

The solution worked great. You learn something new every day. Thanks.

NJ 4 years ago

Can't believe how much time I wasted before I got here. You saved my external hd, here is my firstborn in recompense.

admirer100 4 years ago

wow pal your great thanx for the fix

varma 4 years ago

problem with my bluetooth device in my laptop

plzz giv assistance dude!!

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jeanneCorvan 4 years ago

You have saved my day. My cat had knocked my 2TB (totally filled) external drive off the table a few weeks ago and today all of a sudden nothing there. I felt the worst had happened until I tried your solution. Thank you so much. Unbelievable and I had tried everything else. Trouble with these large drives is you have to buy another 2TB is you want to back it up so I don't do it.

Awesomeness 4 years ago

You... are... BRILLIANT MAGNIFICO SUPERB OF A GENIUS... took me 3 days to find this web it did. And thank you for ur brain as it had save my hardisk.

Shookrullah 4 years ago

Perfect, in our orginazation i got the problem with laptop, then i have unpluge adapter and also remove the battery for at least 3 minutes, after that the problem is solve....

Dr Veranis 4 years ago


I have bought a 2T External HD.

I connected it on my lap top but nothing , only the repeatedly sound of plugging and unplugging. I tried it on my brother's lap top and it worked ( xp )

but on mine (win7) ...nothing ! what can I do ? Thank you.

vipul 4 years ago

my laptop windows 7 is not showing change settings option for mouse give me solution dude!

Ram 4 years ago

But still the problem not solved

Gupta 4 years ago


I Did as you say. Still Same problem. Same error i am getting error code 43

Thanks 4 years ago

It did the trick

Robbie 4 years ago

Thank you so much, what a strange fix - but it worked!

Peace 4 years ago

Having exactly same prob, but these set of instructions arent working at all

Miso 4 years ago

Thank you, worked i did One Mississippi, two Mississippi ..

advaneil 4 years ago

Great information...Thanks a lot for all do and share with us..


arch 3 years ago


grateful 3 years ago

I love you sir.

Chrissy 3 years ago

Thank you so much!

I was at an absoloute point of panic when I found this. I immediately tried it, and lo and behold, my hard drive worked. I'm still pissed off at myself that I didn't think to try it...

irideckard 3 years ago

Hello. Thank you for your tip, my problem was solved, but only after I also disabled the "Allow the computer to turn off this device to save power" function in Device Manager -Universal Serial Bus cotrollers -USB Root Hub(for all 5 of them!) -Properties -Power Management tab.

johnson 2 years ago

USB device not recognised ( error code 43) relating to printer

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