Sometimes users, when trying to connect and continue using USB devices (flash drives, external hard drives), get a system error that says that this USB device is not recognized. Why such a reaction to the device occurs, it’s hard to say for sure. Let's try to figure out what is the reason for this behavior of the operating system and how to fix connection errors.
The USB device is not recognized. Why is there such a failure?
To begin with, not a single Windows-system is immune from the appearance of short-term failures, which can lead to such situations.
Indeed, it happens that Windows does not recognize a USB drive or other device, say, a printer or scanner. However, in the simplest case, this has nothing to do with drivers. Systemic failures themselves, when an increased load on the processor and RAM can be observed, can be the root cause of this phenomenon. But sometimes it’s enough just to reconnect the device (for example, remove the USB flash drive from the port and insert it again). Oddly enough, very often such actions help. Perhaps the device when reconnecting will be recognized after restarting the OS. But this is not the main problem. In some cases, Windows 7 does not recognize USB devices for completely different reasons, which will be discussed later.
Port change
One of the factors affecting the operation of any removable or plug-in device is the criterion for using the corresponding interface. For example, if the same drive is designed exclusively for working with USB 3.0, connecting it to a port with a USB 2.0 interface will not achieve anything.
The conclusion is obvious: just change the port used (usually computers have several connectors, and the port of the third version of the interface inside is colored blue).
USB device not recognized: what to do with drive drivers?
But the main problem can still be called the absence or incorrect installation of drivers for the device itself, although, as a rule, when it is connected, the system automatically recognizes the device and installs the drivers on its own.
If the Windows 7 USB device is not recognized after the first connection, you can use the “native” driver disk (for flash drives, printers, smartphones or tablets, they can be delivered directly upon purchase). If there is no such disk, you can’t even try to reinstall or update the drivers in the “Device Manager” (all the same, Windows will not find anything or let you know that the most suitable driver is installed). This is due only to the fact that the default search will be performed in its own database, and for some non-standard devices the necessary control software may not be there.
In this case, you should ask for a driver search on the Internet by visiting the manufacturer’s website. If the device in the “Device Manager” is visible, but marked as a non-working device, you can simplify your search by using the information about the VEN and DEV identifiers, which can be found on the information tab, setting the equipment ID as the displayed parameter.
USB controller driver issues
But the problem, when the USB device is not recognized, there is a flip side to the coin. The point here is that the root driver may also be a non-working driver of the USB controller itself, because of which the interfaces of the connected device and the port itself may be corny incompatible.
In this case, it is necessary to check the status of the controller in the “Device Manager”. In this case, you need to display all the hidden devices (there may be several USB controllers in the system). Updating drivers or reinstalling them only for non-working devices is not worth it. It is better to update them for all system devices that are related to the USB interface.
Usually this approach helps even when updating software from the system’s own databases. If this does not give the desired effect, then again, you can use the search by identifiers described above.
Viruses
Finally, viruses can also cause situations when the system reports that the USB device is not recognized. Indirectly, their impact may affect the state of drivers and system services. As already clear, in this case it is necessary to perform a full scan of the computer for threats, using portable scanners for this, rather than regular anti-virus programs.
However, the best option is considered to be the use of disk programs called Rescue Disk, which have their own boot records that allow you to use removable media with them on board to start even before loading the operating system itself. For scanning, it is better to select all disks, including the Windows boot loader, and hidden partitions, setting an in-depth scan. Only in this case is it guaranteed that the viruses (if they are, of course) are found and neutralized. An advantage of such utilities is the fact that they are able to find even those viruses that are very deeply rooted in RAM.
What could be more?
Finally, it is worth saying that the connected devices or ports themselves may turn out to be inoperative due to damage. What to do in this case? Try just connecting another similar device or using a different port. In principle, these issues were not considered, since the main emphasis was placed on software problems.
As for printers connected via USB, it is quite possible that the print service is stopped on the system, or the corresponding Windows system component is simply turned off. Try restarting the appropriate services and rebooting the system and printer. But here it is important to understand that if the appearance of a situation is associated with a viral effect, it may very well be that such actions without a preliminary check of the system will lead to nothing.
As for the rest, as it was already possible to notice, the proposed solutions to fix such failures are quite simple and they are mainly associated exclusively with drivers. Therefore, as a first step, you can just upgrade them or reinstall them (you can even remove devices from the system so that when you restart it, it installs the drivers on its own).