Select Run to perform disk diagnostics and fix any issues.Open Utilities and Disk Utility, highlight the grayed-out volume and select First Aid in the top center.If this doesn’t work, you may need to use the Verify Disk utility to make sure everything is working as it should. Open Finder and navigate to the drive in Devices.The volume should shift from gray to normal to signify it has been mounted.
Reboot your Mac to see if it was an open program or app stopping the drive from being detected.Try a different wall outlet if there is one nearby.Change the hard drive power cable if you have a spare.Check the condition of the cable and swap it if you have a spare.Check that the external hard drive has power if it needs it.Check that the cable from the hard drive to your Mac is connected properly.After all, no one wants to waste half a day because they didn’t realize something just wasn’t plugged in properly. Get into the habit of doing this with any computer issues, as it can save time, money, and hassle in the long run. Troubleshooting an External Drive with a Mac First, we will check the basics, and from there we make sure that macOS is set up to display external drives, can mount the drive, and that the drive has no errors on either the disk itself or its file structure.
If your external drive still doesn’t appear, we have a couple of simple troubleshooting tips to fix an external hard drive not showing up on Mac.