How to access an external HDD that's not recognized/working on Mac?

Most of the time, when we connect an external hard drive to our Mac's USB port, we soon see the external hard drive appear on the desktop. However, sometimes, an external hard drive doesn't show up in Finder or disk utility. It can be annoying, especially when transferring data.

What should we do when an external hard drive is not recognized/working on Mac? There are several solutions to solve it:

Solution 1: Check USB connection, USB cable, USB port

If external hard drive is not recognized/working in Finder and disk utility, please check USB connection, USB cable, USB port and then try again.

Solution 2: Check Preferences in Finder

If the external hard drive is recognized/working in disk utility, but it doesn't show up in Finder, please Open Finder ->Preferences -> General tabe" Tick "External disks".

Solution 3: Try data recovery software

If external hard drive is recognized/working in disk utility, but external hard drive is unmountable/unreadable in disk utility. In this siutation, we need to recover data firstly and then reformat it.

M3 Mac Data Recovery is a professional Mac data recovery software which can recover deleted/lost files from emptied Mac trash, recover data from formatted, unreadable, unmountable, uninitialized drive in macOS High Sierra/Sierra/EI Capitan/10.9/10.8/10.7.

Tutorial to recover data from unmountable/unreadable external hard drive with M3 Data Recovery

Step 1: Download, install and then launch M3 Mac Data Recovery on your Mac computer.

Step 2: Select external hard drive

Free Mac data recovery software - M3 Mac Data Recovery

Step 3: M3 Mac Data Recovery is scanning lost data from unmountable/unreadable external hard drive

Scan lost data from unmountable/unreadable external hard drive

Step 4: Select the found files you expect to recover and then click Recover to recover lost data from unmountable/unreadable external hard drive.

Recover data from unmountable/unreadable external hard drive

After data recovery from unmounted/unreadable external hard drive is successfully done, please try to reformat it, it will be working again after format completes.

Solution 4: Seek help from a local data recovery professional

If external hard drive is not recognized by disk utility and any data recovery software, in this situation, generally speaking, external hard drive has hardware issue, please send unrecognized external hard drive to a local data recovery professional for help if we lost the important data.

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