The USB not recognized error that has driven me insane over on number of occasions and I have found a few tricks which might work for you. There are a number of possible solutions so check each one from the most common to the more difficult. USB Solution 1: I discovered that the Dell computers I had 2 USB ports in the front and 4 in the rear of the computer. For some odd reason some of my USB devices will not run on the rear ports and will only run on the front ones. As easy at it might sound simply change the USB sockets around. Pull out a USB plug from say your keyboard and plug in the device you want to use that is not being recognized. If it picks it up let it install the driver and once done try plugging it into another port as the driver is already installed. This normally I could get away with. USB Solution 2: There are many USB splitters around and many are not good. They look like an octopus. If you are using one of those then try connecting the computer with the USB splitter. Many times the splitters are faulty as there is not enough power coming through them. USB Solution 3: This one gets mainly from a mobile phone where it will not pickup the mobile phone. Samsung PC Studio has this problem. Try Solution 1 and Solution 2 as stated above. Startup the software on your computer with the mobile phone disconnected. Once the software is up and running and searching for your phone then only plug in the USB cord into your mobile phone. This normally gets the phone to connect and recognized by the computer. USB Solution 4: You next problem might come after you have installed something like Samsung Kies which is a common problem. The easiest thing to do is to shutdown the computer and leave it for 2-3 minutes. Pull the plug out at the back of the computer (unplug it from the wall socket) so the power can drain out of the power supply of the computer. After 2-3 minutes then restart the computer again. Also check the above solutions as the USB or connectors might be faulty. USB Solution 5: If the above 4 solutions have not worked then you have another issue being that the USB drivers might be corrupt. This is how to fix the driver issue. This method resolves steps where the currently loaded USB driver has become unstable or corrupted. Click Start, then type device manager in the Search box, then click Device Manager. Expand Universal Serial Bus controllers. Right click a device and click Uninstall. Repeat for each device. Once complete, restart your computer. Your USB controllers will automatically re-install. USB Solution 6: If none oft he above fixed it then you should look if the USB has powered down without you knowing and you need to disable this. This method prevents your USB external drive from powering down. Click the Start button, type power plan in the Search box, then click Choose a power plan. Next to your currently selected plan, click Change Plan Settings. Click Change advanced power settings. Click the box to expand USB Settings, then expand USB selective suspend settings. Click Plugged in, then click the drop down menu and select disabled. If you’re using a laptop, click Battery, then click the drop down menu and select disabled. Click Apply, then click OK. USB Solution 7: Oh… If you got that virus hoax telling you to delete a file and you had to delete the usbehci.sys file and now your mouse does not work – You can find that file here. That old chestnut almost slipped my mind. USB Solution 8: (Mobile Phone Problem) The most common issue with this error when it comes to mobile phones is that you have bent the USB connector. Many people plug their phone to charge into the USB connector and after a while the USB connector bends and does not connect properly. The easy solution is to take a toothpick and stick it under the middle part of the USB connector (the part that looks like a tongue in the middle) and just bend it upwards a bit. This solves most of the USB Samsung issues. After a while the cable makes the tongue bend the wrong way and it starts giving the error. If none of these work then you need to check your cable quality. There are loads of poor quality cables out there. These solutions above work on most of the issued. On the other hand you can also check if the USB device needs a driver in order to work especially the mobile phones. Samsung uses a Samsung USB driver in order for it to connect correctly which is located here. The above solutions should however fix 90% of your USB problems.