HOW TO Troubleshoot external drives >

1 Check your screens

We’ve found that when we wake our Mac from sleep, macOS sometimes moves all our drives to the external display or doesn’t re-initialise the USB ports. Unplugging and reconnecting the USB cable(s) will fix the latter.

2 Look at locations

The Finder sidebar includes a section headed Locations, which you may have to scroll down to see: here you’ll see any connected storage devices and your main Mac drive too. If your drive is visible here you can click and see its contents.

3 Check your desktop

If your drive is appearing in Locations but not on your desktop, go into Finder’s Preferences and look under the General tab. If the checkbox for a particular kind of drive isn’t checked, it won’t appear on your desktop.

4 Scan the sidebar

The same applies to the Finder sidebar: it’s possible to prevent certain types of devices or locations from appearing in the sidebar. You can check that in Preferences > Sidebar and enable or disable any items you wish.

5 Use Disk Utility

Applications > Utilities > Disk Utility can fix some drive problems: if the drive is showing in Disk Utility you can select it in the sidebar and then click on First Aid to perform a series of checks. If it finds errors it will then attempt to fix them.

6 Check the format

A new drive might have the wrong file format: some PC formats will not work on a Mac. If the drive is formatted with one of them you can reformat it into something Mac-friendly such as MacOS Extended, but you’ll lose its data.