USB Device Not Recognized (External Hard Drive)
#41
Posted 12 August 2009 - 08:56 PM
Many thanks to Richie66 for his post.
Western Digital drives can be a pain in the neck - my two externals just vanished and became 'Unknown Devices' to Vista.
After searching here I put them on their sides, replugged them and hey presto - there they were! A bit of switch cleaner in the sockets and they now seem fine again.
I had a My Book World which was such a pain I ended up taking the hard drive out and installing it internally.
Time WD got their act together!
Cheers,
Barryt
#42
Posted 23 August 2009 - 09:25 AM
it didn't work so I turned it over to the other side upside down and it didn't work (now it's plugged in this whole time) and then I turned it back over and laid it flat so I could get the hammer to it. And what.da.ya.know the three bongs sounded and WD Button mangager appeared and Wow the unit is now working for the first time in 3 months. Don't know how long it will last but we will see. I think maybe it might have to do with the docking of the Hard Drive's scan. Maybe it was stuck and I popped it back in, anyway now all I have to do is find out where I can get a copy of the original software to reload the Dantz Retrospect for WD & the WD button manager, both of these need to be reinstalled on this new internal HD. I've heard of a lot of things Richie but this one needs to be in the List of Weird computer fixes. Hey you think this calls for a class action suit for a recall and replacement of all of our WD Ext HDrives
#43
Posted 11 November 2009 - 12:26 AM
DJ
#44
Posted 23 November 2009 - 01:20 AM
my first time ever posting on any forum...i'm doing this cause i got a lot of good info from this site that helped me out quite a bit...
so i had the same "usb device not recognized" error, shortly after i tried to use a 4 port usb hub...that screwed everything up...
anyways i read instructions posted on this site by ross_aveling it was a good effort but it worked only half way...
i did restart my system in safe mode and take out the usb devices in device manager and add/remove programs...but that alone didn't help....but when i SYSTEM RESTORED to a date before i used the crummy 4 port USB hub and then switched back to normal mode....it corrected itself....hope this helps....i'm not very IT help inclined but i really hope this helps someone who was feeling like smashing a few things like i did when this happened...
#45
Posted 24 December 2009 - 08:52 PM
Just FYI hope this helps someone.
PT
#46
Posted 01 March 2010 - 06:51 AM
Before I went to college for my engineering degree, I worked repairing audio equipment, as well as lots of other types of equipment. After the degree and a few disappointing jobs, I formed my own company built products for computers, eventually "specializing" in laptops.
Some of the products also used cables, though USB came along late in the history of my company. However, we did have similar problems with cables AFTER they had either been used for a long time, or, somehow bent or twisted or otherwise "stressed". We found that even new cables could be rendered defective by even slight "stretching" caused by normal use.
One of the problems was that the cables were not always soldered to the connectors. Whenever possible, the cable manufacturers crimped connections to connector pins and shells, which saved them a lot of money and, consequently, allowed us to buy cords which did not cost more than the products (such as the current farcical "Monster" cables do). Unfortunately, the metals used in the connectors and the wires in the cables were not always compatible, and we had regular problems with the cables, very much like those reported here.
After switching to high quality connectors and building some of the cables ourselves, the problems more or less went away for a while. However, they eventually returned, and we discovered that the stranded wires used in the cables, which is a number of very thin solid wires twisted together, to allow the cables to flex, the stranded wires were literally wearing out. As the thin wires would break one by one, the resistance of the cables would go up, until finally the cables were either open (due to all the wires breaking) or intermittant (as the ends of the wires touched and pulled apart) or had high impedance as the signal and power currents were carried by smaller and smaller amounts of wire.
I would not be surprised if the problems reported here are due to a similar effect on the cables used with the USB drives. In some cases, the one amp of current required to START the drive, when carried by a cable which has increased its resistance to just one ohm or more, will cause the loss of one volt or more of voltage delivered to the drive, which is enough of a loss to prevent the drive from starting up. As the resistance increases in the cables, the drive may not work at all, as the logic circuits inside are sensitive to power supply voltage also.
Since virtually all manufacturers, such as WD, purchase cable assemblies from companies which specialize in making them in large quantities, I'd suspect that WD either got a warehouse full of low quality cables, or, that their drives require too much power when starting up. I wonder if a large value capacitor connected across the power and ground connections of the USB port(s) would supply enough "surge" power to start the drives up, even though the USB specification for USB 2.0 says that a device may draw no more than 500 mA from the USB connector, since the capacitor would charge up fairly quickly, probably before the drive tried to power up, and would supply a temporary surge of power for a fraction of a second during drive startup, then simply sit idle during ongoing operation of the drive, etc. Perhaps that is too technical but that is what I intend to try if I ever have this problem. I probably have seen the problem without realizing it, as I have had trouble with my "generic" USB drives from time to time....
Perhaps this will help work out what is causing this problem. If it is too "techie", just ignore it.
regards,
Larry
#47
Posted 16 April 2010 - 10:58 PM
#48
Posted 23 May 2010 - 07:38 PM
#49
Posted 02 June 2010 - 12:50 PM
again to solved the mystery of this problem thing..you know what i found out?..the computer cant recognize the flash drive because of POWER that supply into it..yup thats the problem..and after i 100% recover my flash rive and working again i just found out that it has a lot of virus namely: win32/mabazet.A virus , win32/alban.NAB virus ,win32/SALITY.NAR virus , VBS/AUTORUN.CM WORM and more .. as you can see it the virus controll the win32 of the computers system thats why it didnt recognize it and i THINK it holds back the power supply that he needed..
so how did i do it?..
SIMPLE steps..i go to disk manager then at universal bus controller i unistall all my usb root hub 1 by 1 also with the standard universal PCI to USB Host Controller,then at the ACTION tab above it i SCAN Hardware change (note* your usb or flash drive must be inserted to the port so the computer can scan for your drive) then viola,problem solved!! then i opened my 2yrs old granny flash drive with nod32 then all of the items inside found many viruses..dang!!!
my conclusion is this 1.)Power of the usb port may be to high for the flash drive thats why you need to uninstall all drive then scan for it 2.)the power of the viruses
i hope this really help guys..email me or bump this thread if you need for more information about what i did..im cloning my hardisk right now and i just try to solve my flash drive problem for past time coz i read this thread..
I HOPE THIS HELP (im using Transcend JF v33 1gb my OS is windows xp sp2)
#50
Posted 23 June 2010 - 10:45 AM
#51
Posted 07 June 2011 - 04:41 PM
Soooo.... my WD 120GB External stopped working today which freaked me out because I had just used it to back up all my stuff whilst I dropped a new internal drive in my PC. It was working fine after the swap and I've just been pulling files off it as I needed them as to not clutter my new internal drive with unneeded stuff. (I'm OCD about hard drive space... I can't help it).
This morning however, I plugged in the old WD and it gave me the "Unrecognized" error. I tried everything: Power Management, different cables, different ports, turning it on its side, uninstalling, blah blah... nothing worked. I new it was still good because it worked in my laptop just fine.
I kept reading all over the web that it may be a power issue.. that the drive isn't getting enough to properly spin up and enumerate with the USB hub.
Then I realized I had added my printer to my newly rebuilt PC after I had used the external drive to copy some files. You see, I have this "Energy Star" HP USB printer that my dad gave me because he hated it. It really is kind of annoying because there's no easy way to turn it off when not in use.. you have to press and hold the power button like 3 times before it shuts down.
Anyway.. long story short.. I turned off the printer (which also disconnects its USB connection), replugged in the WD and it fired right up! Apparently my "Energy Star" compliant printer is drawing too much energy for my USB hub to also run my WD drive.
So, if anyone is still having trouble, try disconnecting other USB devices to allow as much juice to flow to your drive as possible.
Good luck.
#52
Posted 23 August 2011 - 01:19 AM
The power seems to be intermittent, as the device dies then comes back to life after a few minutes. It dies no matter which USB port (front & back ports) I plug into. It works fine in two other household PC's.
This external drive has it's own AC power supply, so I'm confused.
Does USB power have anything to do with this problem if the external drive has it's own power supply?
I read earlier in this thread that replacing the USB cord can help.
What type of USB cord should I buy?
Additional info (if it matters):
I'm running 64 bit Windows 7 with all of the current Windows updates.
Asus Motherboard: P6T SE
Thanks!
#53
Posted 23 August 2011 - 06:10 AM
I had a faulty power strip that the hard drive was plugged into which caused the intermittent power issues thus generating the error message and transfer failures.
Thanks for the quick replies.

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