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How To Fix An External Hard Drive Not Showing Up In The Sidebar On My Mac?

I'm using a new 13" MacBook Pro, macOS High Sierra, 10.13.3. When I mount any of my Seagate external drives, they don't show up - anywhere. The disks are mounted, and can be unmounted using the disk utility, and I get a warning when I un-plug them without properly ejecting them - because I can't. The drives were working on this MacBook Pro, and they work on other Macs, so the drives appear to be healthy. In Finder Preferences "External disks" is checked, and in the Finder sidebar, Devices are not hidden.

Best Answered by

iBoysoft author Vain Rowe

Vain Rowe

Answered on Wednesday, November 26, 2025

Follow the following steps one by one to make the external hard drive show up successfully on your Mac:

1. Temporarily remove com.apple.finder.plist and test.

Step 1: Close all windows and quit all applications.  

Step 2: Hold the option key down and click the "Go" menu in the Finder menubar.

Step 3: Select "Library" from the dropdown, then the "Preferences" folder.

Step 4:Look for this file.

com.apple.finder.plist

Step 5: Right-click on it and select " Move To Trash" from the contextual menu.

Step 6: Restart the computer.

Step 7: If this doesn't help:

Right-click on the Trash icon in the Dock and choose "Open".

Right-click on the com.apple.finder.plist and choose "Put Back".

2. Reset PRAM.

3. Reset SMC. Choose the method for “On Mac notebooks with non-removable battery”.

4. Start up in Safe Mode.

 

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