If your external hard drive or USB flash drive is not mounted on Mac, try plugging it into another USB port or a USB hub. Solution 2: Check if the USB port/USB hub is unmatchable, damaged or lack of power. Therefore, you need to make sure that the connection, i.e. Sometimes the cable itself will become hot because of a faulty connection. If the unstable connection is the case, your external hard drive would not be mounted even with a slight disturbance. Since the connection between your Mac and external hard drives relies on cables, loose connections could be the cause that your external hard drive is not recognized by your Mac computer. Read more about Mounting a disk How to fix external hard drive not mounting in macOS Catalina/Mojave issue? Solution 1: Check if the hard drive is properly plugged in.
1.3: Check if your Mac is set to show mounted drives on the desktop.1.2: Check if the USB port/USB hub is unmatchable, damaged or lack of power.1.1: Check if the hard drive is properly plugged in.How to recover lost data if Mac won't boot after Mojave update?
