If, when connecting the device via USB interface it is not initialized, not defined operating system and does not display any messages at all, then perhaps the reason is disconnected the controller responsible for this port.
The first thing to do look port status in Device Manager. To run it, enter in the window Run(Win + R) command " devmgmt.msc».
Open section USB controllers and look state USB hub or USB Root Hub. 
The picture shows one of them. disabled. Enable it with the right button − Engage.
You can also go to the section properties- tab Power Management, uncheck the box to allow turning off devices to save power. 
In the same properties, you can check relevance installed drivers, update them if necessary. 
If the controller is marked yellow exclamation mark
then try reinstall its driver, or remove all controllers and execute reboot system, after which they should automatically install and work properly. 
All ports not working
If all ports do not work at once - reboot computer and go to BIOS(key F2 or del at startup). Depending on the type and BIOS versions settings can vary, You should find the options " USB function" And " USB 2.0 Controller”, they must be in the position “ Enabled". Most often they are in the section " Onboard Device Configuration» 
Only the front connectors do not work
If we are talking about a PC, then we should distinguish front And rear connectors. The rear are located directly on motherboard, the front ones are connected to it using a special plume. Therefore, when the front USB stopped working, in the first place check operation of the device when connected to the rear. 
If it is correct, then remove the cover system unit (when the computer is powered off), and then check correct connection front connector cable to system board.
Correct pinout connections can be found in the description of your motherboard, but usually, how to connect is clear from signatures on the motherboard.
Other causes and solutions
If you are using extension or concentrator check the operation of these devices when connected to other ports or on a different computer.
If it's about broken connector USB 3.0, check if its special cable is connected to the appropriate connector on the motherboard.
Check drivers The devices themselves connected through the ports may be the reason for these devices, and not the connectors.
If none of the methods gave results, then this particular port or controller probably has mechanical damage that can be repaired service center.
Peripheral devices such as a mouse, keyboard, webcam, printer are usually connected to the computer via USB ports. In this case, it often happens that one or more ports stop working. That is, when connected to a computer, for example, a flash drive, it is not recognized, the keyboard or mouse may freeze, and the printer may not respond and print pages.
There are several likely reasons why some or all of the USB ports on your computer are not working. Let's try to understand this issue and find out what should be done to restore the normal functioning of the computer.
Checking the BIOS settings
The first thing you should pay attention to is the BIOS settings of the computer. You will need a working keyboard to enter the BIOS. If the keyboard is connected to the computer via USB and it does not work, then you need to connect a keyboard with a PS / 2 connector. Otherwise, you simply cannot do anything.
So, we go into the BIOS, for which, when starting the computer, you must press the enter key, usually it is DEL. There may be another key that is displayed on the screen and is listed in the motherboard manual. After entering the BIOS, find the section responsible for the integrated devices (Integrated Peripherals) or the "Advanced" section. Here you should find the subsection “Onboard Devices Configuration”. It is in it that the parameters responsible for the operation of USB controllers are located: USB Function or USB 2.0 Controller. These parameters must be enabled (Enabled). And if one of them is disabled (Disabled), then hover over it and press Enter, thereby enabling it. To prevent your changes from being reset, you must save them by pressing F10 and confirm the save by pressing the Y or Enter key.
After rebooting the computer, check if the USB ports are working. And if not, then you should look for the cause elsewhere.
USB ports on the front of the computer do not work
As a special case, USB only on the front panel may not work for you. In such a situation, it is necessary to check whether the necessary connectors on the motherboard are connected and whether the wires are damaged. To do this, open the side cover of the system unit and pay attention to the connector at the bottom of the motherboard. The board itself has the inscription USB1 or USB2, as well as on the block itself. The wires from the block go to the front panel, and if they are disconnected or broken in one place, then you have found the cause of the malfunction. Damaged wires should be connected or replaced. It will not be superfluous to check the contact in the connector on the motherboard. It is also worth paying attention to the board located on the front panel. Perhaps there is a short circuit, by the way, such a circuit can be triggered by accumulated dust. So be sure to clean system unit from dust.
Problems with the device itself or the cable
The next source of USB problems can be the cable connected to, for example, a printer. This error is easy to identify and fix. We connect a USB flash drive to the checked connector. If it works, then we try to connect other known good equipment using a suspicious cable, for example, a USB hub. If it also refuses to work, then the reason is definitely in the cable and it should be replaced.
Power outages
There are situations when there is simply not enough power for all devices. For example, when connecting an external hard drive, which uses two USB connectors at once, the printer or keyboard may be turned off. In this case, the power of the power supply is not enough to provide energy to all consumers. In this case, the problem may not appear immediately, but after some time after turning on the computer. There are several ways out of the situation. If you have a low-power power supply installed, for example, 300 W, then it would be logical to change it to a more powerful one, 450-600 W. You can also use an active USB hub (with external power). It will allow not only to increase the number of connected USB devices, but also to power them from a separate power supply.
Another reason that affects the operation of USB is a dead CMOS battery. But at the same time, every time you turn on the computer, you will observe the system time and date that have gone astray. After replacing the battery, the problem goes away. But this is not common, so you should check other possible sources of malfunction.
Missing or incorrect installation of USB drivers
Causes related to software malfunctions in Windows 7/10 can be identified using the Device Manager. If you notice that one or more devices specifically do not work, regardless of the port used, then this may indicate that the problem is in the device itself. Open the Control Panel and go to the Device Manager section. All connected devices will be displayed there. If there are items in the list that have a yellow exclamation mark next to them or an Unknown device instead of a name, then the problem is in this device itself. There may be several possible problems here.
Often USB inputs stop working after reinstalling Windows 7/10. This is caused by improper installation of drivers, or the necessary drivers may not be found at all. You will have to select and install manually.
Often, to fix a problem, you just need to update the driver. So, if automatic windows update, and the system itself was installed a long time ago, then the relevance of the software is lost, may appear system errors. At the same time, the device starts to work incorrectly, or even stops functioning altogether. To update (reinstall) the USB controller drivers, you can use the motherboard driver CD/DVD or download the required drivers from the motherboard manufacturer's website.
You can also turn off the power saving feature for all ports using the Device Manager. Expand the list of used USB devices hidden in the USB controllers, Mouse and other pointing devices, Keyboards sections. Double click on the mouse desired device to open the properties window. Now switch to the "Power Management" tab and uncheck "Allow the computer to turn off this device to save power." Thus, the device will be activated always and under any circumstances.
If some equipment is not recognized, then there may be a problem with the drivers already known to us, as well as a hardware problem, consisting in a lack of contact, cable damage, or a controller malfunction. Moreover, it often happens that when a faulty device is connected, the rest stop working normally. The keyboard starts to freeze, as does the mouse, and the printer stops printing. The problem is similar to a lack of power, that is, the consumption of all power goes to faulty device, in which there may be an ordinary short circuit or other malfunction.
USB ports not working due to damaged controller
If none of the above actions helped restore the USB ports, then you should check the motherboard USB controller, which could have failed. In this case, high-quality repairs and diagnostics should be entrusted to the specialists of the service center. As a way out of the problem, try installing an expansion board, the so-called USB PC controller, which is installed in the PCI slot on the motherboard. This solution is much cheaper than repairing the USB controller of the motherboard, and when using an additional USB hub, the problem with the lack of ports will not be relevant at all.
As you can see, finding and fixing problems with USB ports is a rather troublesome business, and all because there can be a lot of reasons. Consistently finding and eliminating obviously wrong paths will allow you to identify and fix the problem.
Causes of problems due to which they do not work USB ports on a laptop, they can be completely different - from hardware failure to "flying" motherboard drivers or the controllers themselves.
However, usually the user can deal with most problems on his own, without contacting specialists - if he knows how to do it.
If there are a lot of USB ports on a laptop (for example, 3 or 4), the problem may not be so critical, and its solution can be postponed.
But if there are only 2 connectors or the constant need to use connected devices - flash drives, and even printers - the issue should be resolved as soon as possible.
Moreover, some methods will take no more than a few minutes.
First Troubleshooting Steps
Termination message that appears on the screen USB work-ports or the lack of reaction from the laptop to the drive installed in the appropriate slot may indicate.
Sometimes you can solve them with a normal reboot - there is a small chance that the fix will happen automatically.
Increase the likelihood of a positive reboot effect, which really helps sometimes, You can do it in an unusual way:
1 Completely disconnect the laptop from the mains (if it was, for example, charging);
2 Remove the battery and leave the laptop in this state for about 5 minutes;
3 Insert the battery back and turn on the device.
If no messages about idle ports appear on the screen, but the flash drive is still not readable or a peripheral device is not connected to the laptop, it is possible that the problem lies precisely in this equipment.
The assumption is tested by connecting gadgets to other ports of the laptop - or another computer.
Other USB devices
Another problematic situation with USB ports occurs when simultaneous connection to a laptop of a large number of external devices.
For example, the user has already connected three gadgets to four ports ( , and ), after which he also tries to install a USB flash drive.
Sometimes such a drive simply will not be detected by the system - and turning off 1-2 peripheral devices allows you to check the assumption.
Simultaneous connection to a laptop of a large number of USB devices and adapters.
Most often, this situation does not occur when peripherals are connected directly to the laptop, but when using a "hub" (a USB hub that increases the number of connections).
You can solve the problem by reducing the number of connected devices - or even better, by removing the hub and connecting all gadgets directly.
Incorrect BIOS configuration
In the list of ways to solve the problem with USB ports, you can find.
Sometimes, using this interface, it turns out to enable controllers that turn off on their own on the system board.
Activation requires several steps:
- Reboot the system while simultaneously pressing the function keys to enter the BIOS (for some laptops it's F1 or F2, for others it's Del or Esc).
- Select the Advanced or Integrated Peripherals section.
- Go to the USB Configuration menu item and change the parameter value in the USB Controller section (there may be several and with different names) to Enabled.
BIOS interface settings.
After rebooting, the hardware configuration on the laptop will change, and USB ports that were not recognized by the system before that may turn out to be working.
System settings
A battery-powered laptop may automatically turn off some controllers to save power - especially if it approaches critical values.
In this situation, first of all, you should connect the laptop to the network, and then change the power settings, by doing the following steps:
1 Open Device Manager.
2 Select the branch denoting serial bus controllers.
3 Find and open the USB Root Hub subkey.
4 Open the properties of the hub by double-clicking and go to the power settings.
If the problem was wrong settings power consumption, due to which the laptop automatically turned off the ports, there will be a check mark on the item that allows turning off the power of the hub.
By removing it, you can restore the functionality of the ports.
The steps are repeated for each hub if there are several on the laptop.
Prevent the system from turning off USB ports to save power.
Problem with drivers
The problem may be - and in most cases it is - in problems with USB drivers.
You can find the problem by going back to Device manager(via computer properties or by typing devmgmt.msc in mmc).
It is possible that one of the ports is marked in the list with a special icon - yellow triangle with an exclamation mark, indicating a malfunction of the equipment.
The problem can be tried solve in one of 2 ways:
- Try updating the drivers (preferably an Internet connection) in the properties of the USB controller.
- Remove the device marked with a yellow triangle from Dispatcher And restart laptop.
When using the second option, the rebooted system trying to install new software for detected "new" hardware. Sometimes the operation of the port is restored.
For the first option, you may need to find out the ID number by which the Web searches for the corresponding driver - this identifier is located in the device properties on the details tab.
Determine the USB port ID.
The problem, which is the incorrect operation of the motherboard drivers (usually occurs with outdated laptops released several years ago), is solved by downloading and installing the appropriate software.
To do this, the laptop user must first find out - for example, use the AIDA64 application, which is paid, but also works without entering a key confirming payment for a certain trial period.
The name of the device will help identify and msinfo32 command, entered in the "Run" form (called by the keys Win + R).
Determine the name of the motherboard.
You can try to find drivers for the corresponding board on the website of its manufacturer - or on the resource of the company that developed the chipset.
You should know: In the absence of time and experience in finding and updating drivers, you can use the help of the utility. After installation on a laptop, it will independently check and update all the necessary software. The disadvantage of using this method is that, if you do not choose manual setting updates, the application will automatically replace the drivers for almost every detail and even update some programs - this usually takes several hours.
Utility for searching and updating control programs and other applications.
Incorrect operation of the operating system
Replacing this part returns the port (or several connectors at once) to its normal state.
In order to encounter such problems as rarely as possible, the user should not connect a large number of USB devices to the laptop - especially using special splitters ("hubs").
Also worth including automatic installation updates in the corresponding section of Windows - this usually allows the system to solve driver problems on its own.
USB technology is one of the most important of the vast number of technologies that have had a major impact on the computing world. USB (stands for Universal Serial Bus) is a serial interface designed to transfer data to medium and low speed computer peripherals.
This technology has made it work with scanners, printers, as well as external devices (USB flash drives, hard disks external) really light and comfortable. All activities related to USB installation devices are reduced to the “Plug and Play” principle. These devices have become truly mobile thanks to USB technology. To date, USB ports are equipped with laptops, desktop PCs, as well as various gaming devices, cameras, smartphones, navigators, TVs and other devices.
USB 2.0 ports transfer data at speeds up to 480 Mbps, in the USB 3.0 version, the maximum transfer rate rises to 5 Gbps. The USB symbol is a kind of trident, which is drawn on both USB devices and computer connectors.
This technology has already been sufficiently studied and has undergone many improvements, and therefore USB ports rarely cause any problems when used correctly, and troubleshooting associated with them causes little hassle. In this article, we will look at the basic principles of troubleshooting any problems that may arise with USB ports.
- if the USB ports on the motherboard are mechanically damaged, then they should be disconnected from the motherboard (connectors in front of the case) or sealed with tape so that they are not used. Such ports at the first opportunity should be replaced with new ones in the workshop.
- do not connect devices if there are visible mechanical damages USB connectors, and devices, if any external damage case, or there is a smell of burning.
- do not overload USB ports. In them, the current strength is limited: for USB 2.0 - 500 mA, for 3.0 - 900 mA. Do not increase the number of USB ports with different USB multipliers. New motherboards have up to 10 ports, which is quite enough. It is more reliable to purchase an additional PCIe or PCI USB controller than to work through a USB “tee”.
- before connecting USB, in order to remove static voltage, it is recommended to touch the grounded case of the system unit. Static discharges are often the main reason why USB devices fail.
If the USB ports stop working on a laptop, then it becomes very difficult to work on it - you can’t connect a scanner, a printer, or a USB flash drive. Unlike desktop computers, installing an additional USB controller is quite expensive.
When error messages like this “USB device not recognized” appear, in most cases, the problem may be with the USB port. solved this problem quite easily, because it occurs at the program level.
Any hardware device through the driver interacts with the operating system. Most device problems are solved with the help of drivers. This also applies to non-working USB ports. Below we will look at several ways to help troubleshoot USB ports at the software level.
Restart your computer
If the ports suddenly stop working, and the computer does not detect the USB device, then the easiest way to fix a sudden problem is to restart the computer. Restart your computer. If there were no problems when loading the drivers, then such a malfunction will be eliminated after a reboot.
Update in Hardware Configuration Device Manager
If in this moment restarting the computer is not desirable (for example, some important operation is being performed), then without restarting the entire computer, you can “restart” the driver using the Device Manager. To launch it, you need to right-click on the shortcut "My Computer" and select "Manage". Or go to the Start menu and find the Run program there, launch it, and then enter the devmgmt.msc command in the field.
A window will open in front of you, where you need to left-click once on the list of devices, then click the “Action” tab in the main menu and point to the “Update hardware configuration” button. The USB controllers section should appear in the list of devices. If it appears, then your problem has been solved, and the USB ports should work.
Disabling the USB controller
Another way to get the USB ports working is to disable and then reinstall the USB controller. To do this, launch the Device Manager. We find the USB controllers section in the list of equipment. In this section, on each of the devices, right-click, then delete them all. After all controllers have been removed, restart your computer. The controllers will reinstall and the USB ports will become available again.
Update USB Controller Drivers
The reason for the inoperability of USB ports may be damage to the USB controller drivers. The way out is to find the correct drivers and reinstall them. To download the appropriate drivers, you need to find out the manufacturer of a specific USB device port. By installing the correct driver, the issue should be resolved immediately.
Disconnecting other USB devices
It happens that USB ports do not work due to being overloaded when a lot of USB devices are connected. USB hubs sometimes do not provide enough power to connected devices. Some connected device can use all the power of the USB controllers. If the equipment is connected to a USB hub, then reconnect the device to USB port directly.
You can leave the device connected to the USB hub, but you must first disconnect other devices on the hub. Purchase a USB hub that has its own power supply that will provide sufficient power to all devices connected to it.
If none of the above methods helped you, then most likely the USB ports are physically damaged. Or the USB controller is damaged, south bridge on the motherboard in particular. In this case, it is best to repair or replace the USB port controller at the service center.
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Many of our readers have asked for an explanation Why are the USB ports not working? and also why the error pops up " Error. USB device not recognized". Finally, I found the time to write this long-awaited article. USB ports are not always the cause of a connected device not working.
Very often, the external device itself fails, which is why an error pops up about a faulty USB port. Before moving on to the next steps, make sure the USB device you want to connect is working (check with a friend or on another computer). If you are sure that your device works, then this article is for you.
Causes of the problem
They can be completely different, but you need to find out the exact reason due to which USB ports not working.
- If the above methods did not help and still USB ports not working, try to go to "Device Manager" and check the "Controllers" section for devices with a yellow exclamation mark. If present, double-click on the device and read the reason for that error.
- Perhaps the USB ports are not working due to incorrectly installed drivers or their complete absence. The article will help you deal with this.
- It is possible that USB ports not working due to the usual ones, but by installing and scanning the computer, we can find and
