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How to fix USB hard drive not mounting in Mojave on 2017 MacBook Pro?

I have a 2017 MacBook Pro, which only has USB-C ports. I have some hard drives with USB 2.0 cables connected to USB hubs that won't mount. I can see the drive listed in Disk Utility, but I cannot mount the drive(s). I can mount the drives on an old 2010 MacBook that I have, but I really need to access the files on this and other drives on my newer MacBook Pro. Does anyone have a solution to this? I've read so many threads and tried a bunch of Terminal commands with no success. Please! Help!

Best Answered by

Anna Yuan

Answered on Tuesday, December 3, 2024

First, try connecting the drive with the other USB-C ports on the Mac laptop. If useless, continue to try using just a USB-C to USB-A adapter, or another brand of the hub and check if your hub has its own power supply.  

If the problem still exists, try to reset SMC and PRAM to see if it's workable. 

To reset SMC on Mac, here's how to do it:

  1. Shut down and unplug the power adapter on your Mac.
  2. On the built-in keyboard, press and hold the Shift + Option + Control keys on the left side and press the power button and hold all of these down for 10 seconds.
  3. Release all four keys.
  4. Connect the power adapter and then turn the Mac on.

Check if the drive can be mounted successfully in Mac Disk Utility, if not, proceed to reset NVRAM/PRAM in macOS:

  1. Shut down your Mac completely.
  2. Press the power button and simultaneously hold down the Option + Command + P + R keys for about 20 seconds.
  3. Release the key combination when you hear the second startup sound from your Mac.

Please be noted that before resetting SMC and PRAM on your Mac, unplug your USB drive from your Mac and after restarting your Mac, connect it again to see if the problem has been fixed. If unfortunately, none of the above methods work, try to ask the drive manufacturer or Apple Genius for help.