Suddenly my computer doesnt recognize the printer, MP 530. Says unknown device on usb port and cannot load the driver. When I try the printer on another computer, I get the same message. Could the cable have gone bad?

Method 1 - Unplug Computer So how did I finally fix the problem? Well, if you are lucky, it's a super simple solution! Try this method first and if it works, you'll have saved a lot of time.
Simply unplug your computer from the power supply. Yes that is it! Note that this does not mean just turning off your computer using the power button because most modern computers don't actually turn off completely and the motherboard will still get power. This is useful sometimes if you want to remotely wake up a computer, etc.
The motherboard is where all of hardware of the computer connects to, including the USB ports. Sometimes the motherboard needs to be "rebooted" because things can go wrong, i.e. all or some USB ports suddenly stop working. The small microprocessor on the motherboard will reload the drivers and your USB ports should hopefully be recognizing devices again.
So first turn off your computer using the Shut Down option in Windows or pressing the power button and then UNPLUG the PC from the wall outlet. Let it sit for several minutes and then plug it back in.
Method 2 - Update Device Driver If Windows is not able to recognize the device, you may also see in Device Manager that the device shows up as an "Unknown Device". You can get to Device Manager by clicking on Start and typing in devmgmt.msc or by going to Control Panel and clicking on Device Manager.
In that case, you should right-click on Unknown Device, click on Properties, then the Driver tab and then click Update Driver.

If this doesn't work, you can also try to download the driver for your device from the manufacturer's website. If the USB device is just a flash drive, then it's probably not a driver issue. However, if you are installing a USB printer, drawing pad, etc, then it might be worth downloading the driver for that specific device.

Method 3 - Restart & Disconnect USB Devices The next thing you can try is to disconnect all USB devices and then restart the machine. once you have restarted, try to connect the USB device that was causing the problem.
If that particular USB port doesn't recognize it, try another one. If the device is recognized by a different USB port, there could be a hardware problem with one of the USB ports. If no USB port recognizes the device, then keep reading because it's probably something else.

Method 4 - USB Root Hub Another thing you can try is to open Device Manager, expand USB Serial Bus Controllers, right-click on USB Root Hub and then click on Properties.
Click on the Power Management tab and uncheck the Allow the computer to turn off this device to save power box. If you have more than one USB Root Hub listed, you need to repeat these steps for each one.
Click OK and then restart your computer. Try to reconnect the USB device and see if it is recognized. If not, go back to the power management tab for each one and check the box again. If it does recognize the device, then leave them unchecked.

Method 5 - Connect Directly to PC A friend of mine ran into this issue and the cause ended up being his USB hub. He only had three USB ports on his computer, so he bought a hub where he could connect an additional 8 USB devices.
I guess this proved too much for his computer and it just started sporadically not recognizing various devices. After removing the hub and connecting the device directly to the computer, it worked just fine.
We haven't really been able to find any other solution to this problem other than reducing the number of items connected to the hub. Actually, one other solution worked, but it meant having to buy a new USB hub with more power.
If you are having this problem with Windows 8 or Windows 8.1, then you might be in luck. Microsoft has released a fix for Windows 8 not detecting USB devices properly. Make sure to install this hotfix if running Windows 8.
Method 6 - USB Troubleshooter If nothing has worked so far, you can download the Windows USB Troubleshooter Fixit tool. It's a free tool that works with Windows XP, Vista and 7.
You can either have the troubleshooter fix the problems for you or select the fixes yourself. I would just let it fix them for you since the choices can sometimes be confusing and technical for the novice user.
Method 7 - Update Generic USB Hub If you are getting the Unknown Device error in Device Manager, you can also try one other thing. Open Device Manager and then expand Universal Serial Bus Controllers.
You should see at least one item called Generic USB Hub. On some computers, you might see two, three or more of these. Right-click on the first one and choose Update Driver Software.
When the update dialog pops up, choose Browse my computer for driver software.
When the update dialog pops up, choose Browse my computer for driver software.

The possible explanation to this issue would be than the usb port is very old or damaged and it doesnt recognize the ipod usb cable
you should try to update the usb drivers or buy an new usb interface car if you have a desktop

Hi, 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!

usb device not recognized

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".

unknown usb 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!


Have a nice day...

You mentioned that you uninstalled the unknown device from the Device manager. If you uninstall it then connected your usb flash drive you will see an error again on your device manager. This means that the driver for your usb port is not properly installed.

To install it, visit dell website, look for the model of your machine and locate the driver, download it then install from your machine.

If you are using a multi port USB adapter that allows you to plug many devices into one USB port it may interfere with the scanner. Try uninstalling your Epson driver then download the newest one from the Epson website. http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?oid=88368&prodoid=63070478&BV_UseBVCookie=yes&infoType=Downloads&platform=All&x=27&y=14

Install the newest driver first then plug your scanner into a single USB port on the computer instead of the multi port.

try using different USB port. if the it is unknown device. means the machine didn't recognized the device. you may have to install the device driver. (windows is a funny thing).

There are few things to remember using USB.

• If your System is in hybernation mode, don't remove any attached USB device, because it will damage your USB driver. This is one of the known problem from microsoft.
• If you have to remove any USB device use 'Safely Remove Hardware'.

To remove currepted USB drivers its not enough to remove your printer drivers.

1. You should un-install the 'Universal Serial Bus Controllers' from Device Manager.
2. Then re-boot to clean registry.
3. Install the 'Universal Serial Bus Controllers' using XP Setup CD.
4. Then check the Mass storage, PDA etc, it should recognized by XP.
5. Then install printer driver (don't attach printer to system untill setup finish or setup says to connect).

I think it will fix.
Please let me know your feed-back.

Thanks
Iqbal

pls i want to copy for cd the driver about the photocopier ( canon multi function 4150) to install to the pc

Possibilities:
1) One of your USB devices have faulted, or is causing a resource conflict (or similar)
-- Remove all USB devices, and reboot.
2) Your USB chip/ports have been damaged.
-- Find a spare HardDisk or bacjup your data and re-install Windows and see how that goes.
3) Your Power Supply Unit (PSU) isnt supplying enough power to your PC (usually caused by a Video card upgrade). Try a more powerful PSU ... 400watts should do the trick
4) Bad memory (RAM) can cause wierd problems. run memtest for an hour to make sure your memory is ok





It seems that many people are still getting the 'USB Device not Recognized' problem from time to time. Unfortunately there is no easy fix.
Firstly, it's recommended that you make sure every one of your motherboard drivers are completely up-to-date, but you probably already knew that.
In XP, after a USB port isn't used for a long while the USB driver built into the OS sets the OHCI controller to suspend. When you plug a device back in, it can sometimes fail to 'wake up' properly. This problem was supposedly fixed in SP1 but there is a related registry hack that may still be able to help.
Run regedt32.exe and navigate to;
HKEY_LOCAL_Machine\SYSTEM\CurrentControlSet\Services\Usb
Create the Usb key if it doesn't already exist. Under this key, create a new DWORD value called DisableSelectiveSuspend and give it a value of 1. Then restart the PC.
A long shot perhaps, but I recall having similar problems with a USB hub built into my Microsoft keyboard and adding this key seemed to solve it. It wouldn't hurt in trying .
Alternatively, removing all entries relating to USB in Device Manager and all associated USB drivers will force XP into refreshing the USB driver stack.
Begin by unplugging all USB devices, then use Add/Remove Programs in Control Panel to uninstall any USB driver software. Next, boot up into safe mode and go to Device Manager. Once in device manager make sure 'Show hidden devices' is checked under the View menu. Uninstall all device entries in this order;
1. USB peripheral devices (printers etc.)
2. HID and/or Composite USB (Human Interface Devices) You're using PS/2 input devices so you may not have this entry.
3. USB Root Hub(s)
4. USB Host Controller(s) (Universal or Enhanced Host Controllers)
Then boot back into Windows (not safe mode) and it should populate the Root Hubs & Host controllers again. Proceed to plug your USB devices back in, starting with your powered hub. Be aware that most USB printers and scanners need to have their drivers installed first before you plug them in.
Hopefully some of this may be of help, let us know how you get on.