This wikiHow teaches you how to troubleshoot USB port problems on Windows or Mac. There are several reasons why a USB port may stop working: a fault with the driver, hardware, or the USB device itself. After checking the USB ports on your computer, you can check Device Manager on Windows, or try resetting the System Management Controller (SMC) or NVRAM on a Mac. NVRAM and PRAM are special types of memory that store certain firmware and device settings for Macs; resetting this memory can resolve existing USB glitches.
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Method 1 of 4: Checking USB Port
Step 1. Look into the USB port
If you think the USB port isn't working, check the inside for dust, debris, or stuck objects.
Step 2. Connect multiple devices on the problematic port
If a certain device doesn't work on the USB port, try connecting another device to see if it doesn't work either. If these other devices work, it's likely that the problem is with the previous device instead of the USB port.
Step 3. Connect the USB device to another port
If the USB device doesn't work on a certain USB port, try plugging it into a different port. If possible, use another computer. If the USB device works in these other ports, the problem is in the previous USB port.
Step 4. Check if the USB port is loose
When you insert the device into an unresponsive USB port, try shaking it up and down to check for slack. Do it carefully so as not to add to the damage. If this part is loose, the device will be difficult to connect.
Step 5. Restart the computer
If you've gone through the troubleshooting steps and the USB port is still not responding, try restarting your computer. This step will refresh a lot of hardware and fix various issues.
Step 6. Reconnect the device with the USB port
After you restart the computer, plug the USB device back into the port and see if it works this time. If the device is still not working, check device manager.
Method 2 of 4: Checking Device Manager in Windows
Step 1. Click the Windows Start icon
This button displays the Windows Start menu. From the start, the Windows Start menu is in the lower-left corner of the screen. It's located in the Windows taskbar.
Step 2. Type devmgmt.msc
This command searches the Device Manager in the Start menu.
Step 3. Click on Device Manager
It's next to the printer-like icon.
Step 4. Click the computer name
Usually, the computer name is at the top. Click to highlight it.
Step 5. Click the “Scan for hardware changes” icon
This icon resembles a computer screen above the Device Manager. The text changes to " Scan for hardware changes " when the cursor is hovered there. This step forces the computer to check all of its hardware. Hopefully, the previously undetected port is now working again.
Step 6. Connect the device to the port
After scanning for hardware changes in Device Manager, connect the USB device to the port that was previously not working. If successful, the port has been fixed. If not, uninstall (uninstall) the USB controller in Device Manager.
Step 7. Double click Universal Serial Bus controllers in Device Manager
You need to scroll down to find "Universal Serial Bus controllers". Double click to expand it and display all devices and USB drives.
Step 8. Right-click the USB controller
This option is under "Universal Serial Bus controllers". The device name can be different, but look for the keyword " controller ". Right-click to open a popup menu.
Step 9. Click Uninstall device
This option is in the popup menu when you right-click the device in Device Manager. This step unmounts the USB controller device. Repeat for all other USB controllers in the "Universal Serial Bus controllers" list.
Step 10. Restart the computer
After unmounting the USB controller, restart the computer so that Windows scans for all hardware changes and reinstalls the installed USB controller.
Step 11. Connect the device to the USB port
After restarting the computer, check to make sure the USB port is connected to the device. If the device is working, your problem is solved. If the USB port is still not working, the problem is in the hardware and needs professional repair.
Method 3 of 4: Resetting the System Management Controller on Mac
Step 1. Shut down your Mac
To do this, click the Apple icon in the upper right corner, and click "Shut down" (turn off the power).
Step 2. Reset SMC
How to reset SMC varies depending on your Mac model:
- MacBook, MacBook Pro, and MacBook Air: press and hold Shift+Control+⌥ Option+Power until the light on the power adapter flashes or changes color.
- iMac, iMac Pro, and Mac Mini: unplug the power adapter, then press and hold the Power button for 5 seconds or more, then reconnect the power adapter.
Step 3. Press the power button
This button restarts your Mac with an SMC reset.
Step 4. Connect the device to the USB port
After resetting the SMC, check if the USB port is working on the connected device. If yes, your problem is solved. If not, try resetting the NVRAM or PRAM.
Method 4 of 4: Reset NVRAM & PRAM on Mac
Step 1. Turn off the power of the Mac
To power off the Mac, click the Apple icon in the top right corner, and click "Shut down".
Step 2. Press the Power button
This step will reboot (reboot) the Mac.
Step 3. Immediately press and hold Command+⌥ Option+P+R
Press and hold this button as soon as your Mac starts speeding up and hold it down until you hear a sound and the screen flashes. Then, the Mac will speed up as usual.
Step 4. Connect the device to the USB port
after resetting the system management controller, check to see if the USB port is working when connected to the device. If it works, the USB port has been fixed. If the port is still not working after the SMC and NVRAM reset, there may be a problem with the USB port that needs professional repair.
