Want to highlight a helpful answer? Upvote!

Did someone help you, or did an answer or User Tip resolve your issue? Upvote by selecting the upvote arrow. Your feedback helps others! Learn more about when to upvote >

Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

USB problems on High Sierra 10.13.4

I have an iPad Pro on iOS 11.4 and a MacBook Pro on 10.13.4. The left USB keeps rapidly connecting and disconnecting iOS devices. However, in system report the USB is has the required current available when this happens, but there isn't any current being requested. When the devices connect fine, the readings in system report are normal, devices is asking for x current, port is giving x current and y to spare. This only happens to my iOS devices. Although my phone (Android) says left port charges slower than right port, but the system report power readings say everything's fine. In the past, the same port has been slow to pick up USB memory sticks, but that resolved itself a long time ago. No problems with right port.


What can I do? The laptop is out of warranty now (3 1/2 years old). I've tried resetting the PRAM already and cleaning the port as best as I could.


Bonus question, how do I reseat an L key that likes to pop out of joint when pressed on the corner? I've tried before, but no joy. Don't want to remove the key to do it.

MacBook Pro (Retina, 15-inch, Mid 2014), macOS High Sierra (10.13.4)

Posted on Apr 20, 2018 12:28 PM

Reply
Question marked as Best reply

Posted on Apr 20, 2018 12:39 PM

A Troubleshooting Procedure that may Fix Problems with macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.


Be sure to backup your files before proceeding if possible.


  1. Shutdown the computer, wait 30 seconds, restart the computer.
  2. Disconnect all third-party peripherals.
  3. Resetting your Mac’s PRAM and NVRAM
  4. Reset the System Management Controller (SMC)
  5. Reset your Startup Disk and Sound preferences.
  6. Start the computer in Safe Mode. Test in safe mode to see if the problem persists, then restart normally.
  7. Use Apple Hardware Test to see if there is any hardware malfunction.
  8. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
  9. Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
  10. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
  11. Download and install the OS X El Capitan 10.11.6 Combo Update or 10.12.6 Combo Update or Download macOS High Sierra 10.13.4 Combo Update as needed.
  12. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
  13. Erase and Install OS X Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:
  1. Select Disk Utility from the Utility Menu and click on Continue button.
  2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
  3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
  4. Set the Format type to APFS (for SSDs only) or Mac OS Extended (Journaled.)
  5. Click on the Apply button, then wait for the Done button to activate and click on it.
  6. Quit Disk Utility and return to the Utility Menu.
  7. Select Reinstall OS X and click on the Continue button.

If none of the above helps then see How to Downgrade macOS High Sierra and macOS Reversion- How to Downgrade from High Sierra.

1 reply
Question marked as Best reply

Apr 20, 2018 12:39 PM in response to CursedDice

A Troubleshooting Procedure that may Fix Problems with macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.


Be sure to backup your files before proceeding if possible.


  1. Shutdown the computer, wait 30 seconds, restart the computer.
  2. Disconnect all third-party peripherals.
  3. Resetting your Mac’s PRAM and NVRAM
  4. Reset the System Management Controller (SMC)
  5. Reset your Startup Disk and Sound preferences.
  6. Start the computer in Safe Mode. Test in safe mode to see if the problem persists, then restart normally.
  7. Use Apple Hardware Test to see if there is any hardware malfunction.
  8. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
  9. Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
  10. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
  11. Download and install the OS X El Capitan 10.11.6 Combo Update or 10.12.6 Combo Update or Download macOS High Sierra 10.13.4 Combo Update as needed.
  12. Reinstall OS X by booting from the Recovery HD using the Command and R keys. When the Utility Menu appears select Reinstall OS X then click on the Continue button.
  13. Erase and Install OS X Restart the computer. Immediately after the chime hold down the Command and R keys until the Apple logo appears. When the Utility Menu appears:
  1. Select Disk Utility from the Utility Menu and click on Continue button.
  2. When Disk Utility loads select the drive (out-dented entry) from the Device list.
  3. Click on the Erase icon in Disk Utility's toolbar. A panel will drop down.
  4. Set the Format type to APFS (for SSDs only) or Mac OS Extended (Journaled.)
  5. Click on the Apply button, then wait for the Done button to activate and click on it.
  6. Quit Disk Utility and return to the Utility Menu.
  7. Select Reinstall OS X and click on the Continue button.

If none of the above helps then see How to Downgrade macOS High Sierra and macOS Reversion- How to Downgrade from High Sierra.

USB problems on High Sierra 10.13.4

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.