One unrealistic aspect of modern science fiction films is that future technology never seems to suffer from mundane problems; interstellar star cruisers never have finicky Wi-Fi or unresponsive USB ports, for example.
Here in the real world, these kinds of annoying problems happen all the time, and USB ports that fail to work quite the way they should are at the top of the list. If you encounter a USB port that works intermittently, won't charge, or doesn't recognize a device, here are the best seven ways to try to fix the problem.
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Try a different USB port
When you start troubleshooting a USB problem, it may be unclear where the problem resides. It could be related to the device you're trying to connect, the cable, the USB port, software on your computer or something else. Start with the USB port — unplug the device and plug it into a different USB port. If it works, great — there is likely something awry with the port you were using. But if it's still not working, move on to the next troubleshooting step.
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Replace the USB cable
Another likely culprit is the USB cable, especially if it's old or has been roughly handled. It's not uncommon for a USB cable to fray or break under the insulation, so it might not work right anymore even if there's no visible damage. Change the cable and see if that resolves the issue.
Clean the USB port
USB ports were seemingly not designed with routine day-to-day use in mind. Not only are USB-A ports almost-but-not-quite symmetric, making them very challenging to insert properly on the first try, it's easy to get dirt and debris accidentally wedged in the port itself in routine use. In extreme cases, that dirt can prevent the port from working correctly. Use a bright flashlight and peer into the port. If you see anything in there, use a very thin, non-metallic tool like a toothpick to carefully clear the port. Don't use blasts of canned, high-pressure air, though, or you run the risk of forcing the debris further into the port.
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Restart the computer
If you still don't know what the root cause is, it might be a good idea to restart your computer. Turning it off and then back on again can flush out any corrupt data and reset device drivers automatically. After the Mac or PC returns to life, often a failed USB port will work again normally, making it a very simple fix.
Scan for hardware changes (in Windows)
If you use Windows, sometimes the computer may stop recognizing your USB port or device. This is especially true if you unplug and re-insert a USB cable too quickly. One way to resolve this issue is to let Device Manager scan your system for hardware changes. Click Start, type Device, and click Device Manager when you see it appear in the search results. In Device Manager, ensure your PC at the top of the device tree is selected. Then click Action in the menu bar, and choose Scan for hardware changes. After it's done, try your USB port again.
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Reset the System Management Controller (on a Mac)
If you have a Mac, you might need to reset the system management controller (SMC). If you have an iMac, Mac Pro, or Mac Mini, start by shutting down the computer and unplugging it. Press and hold the power button for five seconds, and then reconnect the power cord and start it normally.
For most other Macs, shut down the computer. Press and hold the Shift + Control + Option keys, then without releasing those keys, press and hold the power button. Hold them all for 10 seconds. Release all the keys and the power button at once. Turn the Mac back on and see if that solved your USB problem.
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Reinitialize your USB controller (in Windows)
Similar to resetting the SMC on a Mac, you have one other option in Windows: resetting the USB controller. Click Start, type "device," and click Device Manager when you see it appear in the search results. In Device Manager, find the entry for Universal Serial Bus controllers and click to expand it. Right-click the first entry in the list, and then click Uninstall device to remove it. Then repeat that over and over for every device in the Universal Serial Bus controllers list. When you're done, restart your computer. When it boots, Windows will automatically scan your hardware and reinstall your USB controllers, hopefully correcting your problem in the process.
Freelance Writer
Dave Johnson is a technology journalist who writes about consumer tech and how the industry is transforming the speculative world of science fiction into modern-day real life. Dave grew up in New Jersey before entering the Air Force to operate satellites, teach space operations, and do space launch planning. He then spent eight years as a content lead on the Windows team at Microsoft. As a photographer, Dave has photographed wolves in their natural environment; he's also a scuba instructor and co-host of several podcasts. Dave is the author of more than two dozen books and has contributed to many sites and publications including CNET, Forbes, PC World, How To Geek, and Insider.
