Mac USB ports not working, how to fix?

Mac computer's USB ports stopped working or not working at all, how to fix?

Today, Universal Serial Bus (USB) is one of the main connection interfaces available. USB is used extensively, from input devices (keyboard/mouse) to external storage and output devices (printers, speakers/headphones). As USB ports are used for a wide range of devices, an inactive port can become a major problem. First, ensure the problem is with the Mac USB ports - the easiest way is to try a few separate devices using the same connections.

Also, ensure that cables are in good working condition with no damaged, burnt spots. If other separate devices and cables do not work, this indicates a problem with the Mac USB port/s. This is a common problem, and not model specific. Therefore, you might encounter this frustrating situation on any Mac computer (MacBook, MacBook Pro, MacBook Air, iMac, Mac Mini, or Mac Pro). Although this may seem to be a hardware issue, a number of possible solutions are available without replacing the port or performing a fresh installation of mac OS. Firstly, you can try to reset a number of built-in controllers with the methods outlined below.


Table of Contents:

Reset SMC to solve randomly-occurring USB port problem

If you are sure that the devices connected via USB are working properly, the ports are clean and connection is secure, you can try to reset the System Management Controller (SMC). SMC controls computer power consumption, battery charging and functionality, thermal and fan activity, GPU and video mode functionality/video output, sleep/wake modes and led lightning management, and other hardware functionality. To reset this controller on MacBook, MacBook Pro, and MacBook Air, begin by shutting down the computer and connecting a power adapter. Next, hold down a combination of the Shift, Control, Option, and Power keys for a few seconds and observe the power adapter light. When it blinks or changes color, release the key combination. Finally, boot the computer in the usual way by clicking the power button. After an SMC reset, the USB ports should work correctly. Test each one individually. Detailed information about how to reset System Management Controller on all Mac computers and common issues relating to SMC can be found in this article.


[Back to Table of Contents]

Reset NVRAM or PRAM on the Mac

If resetting SMC does not solve USB-related problems, try to reset the NVRAM/PRAM. The Parameter random-access memory (PRAM) and Non-Volatile random-access memory (NVRAM) stores information about various USB components, such as keyboards, mouse, trackpads, and others. Resetting these might solve USB problems. To reset NVRAM/PRAM on a Mac, first restart it. When the computer starts booting, hold down the combination of Command, Option, P, and R keys. Keep holding the combination until you hear the startup chime (additionally, the screen might flash). Release the buttons and let the system boot as usual. Once the computer has loaded completely, the USB ports should be working. Test each port with a number of separate devices.


[Back to Table of Contents]

Additional tips relating to USB port issues

  • If just one port stops working properly while devices connected to other ports work, ensure the problematic port is clean and the connection is physically secure. If you are sure the port is in good condition and resetting the SMC and PRAM/NVRAM does not solve the issue, consider avoiding this port and use a USB hub connected to another functional port. Alternatively, launch Apple's built-in hardware diagnostic tools to check for hardware issues.
  • If the Apple computer has come into contact with any kind of liquid, immediately shut down the system and disconnect it from the power adapter. Clean and dry out the device to prevent any permanent damage. Remember, liquid can destroy computer components immediately or result in loss of hardware functionality, including USB.
  • If some USB devices work on your computer, whilst others do not, check the device's compatibility with the Apple product version to which you are connecting. Some devices require specific hardware drivers from the manufacturer to achieve full functionality or to work correctly (special use devices, modern scanners, etc.).
  • If there are any firmware and operating system updates available, install them. Updates are often released to fix various hardware and software bugs. To check available updates on Mac computers, launch the App Store application, select the Updates tab, and check for available updates. You are advised to create a backup of the hard disk before updating the operating system.

[Back to Top]

About the author:

Tomas Meskauskas

I am passionate about computer security and technology. I have an experience of 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an editor for since 2010. Follow me on Twitter to stay informed about the latest tech news or online security threats. Contact Tomas Meskauskas.

Our guides are free. However, if you want to support us you can send us a donation.