External hard drive recognized but not accessible

Question

Level 1

16 points

External hard drive recognized but not accessible

Since yesterday my external hard drive (WD Elements 2TB) is not accessible via my Macbook Pro retina, anymore. It worked perfectly before -- in fact, it worked half an hour earlier, but suddenly will not mount anymore. Additionally, disk utility will not load disks while the HDD is connected via USB but instead show "loading disks" all the time. As soon as I disconnect the HDD, it will show my internal SSD as normal. Also, the HDD is indeed visible in the "USB" section of the "Hardware" window of my Mac when it is connected. I also hear and feel the HDD running.

The HDD works normal when plugged onto another (Windows) computer. And another external hard drive that I own also does with my Mac, as do USB sticks.

All of the described circumstances hold true no matter which USB port I use.

Where is the problem located and how can I possibly solve it? I am grateful for suggestions.

MacBook Pro (Retina, 13-inch,Early 2015), OS X El Capitan (10.11.5), null

Posted on Oct 20, 2016 1:56 AM

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Answer 1

david_hb Author

Level 1

16 points

Mar 12, 2017 9:30 AM in response to dwb

Please, anyone, there has to be a a way to repair external hard drives on a Mac?!?! My Macbook just froze and after the hard reboot it once again corrupted BOTH of the mounted external hard drives (that I had mounted for backupping, how ironic). Now I have to repair both of them on a WINDOWS system (taking about 6 hours each), because there is no Mac tool for it?! Why should I ever buy a Mac if I need a Windows system to cure iOS's flaws?? This is absolutely hilarious! I wonder why I was dumb enough to buy such a flawed device. Well, I will not that mistake in the future again...

Anyway, if someone knows a way how I can stop the Mac from wrecking my hard drives, or at least fixing it again, I would be grateful for further help.

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Answer 2

dwb

Level 7

33,244 points

Oct 20, 2016 5:50 AM in response to david_hb

How is the hard drive partitioned and formatted? My first suspicion is a damaged disk directory or partition table. If the drive has only one partition and is formatted for Windows I suggest running a Windows disk utility program to repair the directory. If the drive has both a Mac and a Windows specific partition you'll probably need to attempt repairing it with another Mac rather than a Windows computer. (But I could be wrong, this is something I've not tried to do from a Win box.)

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Answer 3

david_hb Author

Level 1

16 points

Oct 20, 2016 5:57 AM in response to dwb

Thanks for your response. The disk is ExFat formatted.

Indeed the problem seems to have stemmed from a corrupted file system. When I connected the HDD to a Windows PC, it gave some 'corruption warning' and I could only read, but not write, data. I got error "0x80071AC3" displayed and by searching the web was able to fix this with the "prescribed" checkdisk scan on the Windows machine.

Now it works again.

I just wished that my Mac also gave me the opportunity to fix the problem. Is this a Windows-specific problem and thus I am not able to fix this via my Mac?

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Answer 4

dwb

Level 7

33,244 points

Oct 20, 2016 6:46 AM in response to david_hb

Whatever the directory error was it was bad enough that the drive couldn't even be mounted by the Mac. Unmounted, Disk Utility couldn't fix it or report an error except for the obvious one you were seeing - it wasn't mounting! (Sometimes we techs just have to use what we observe 🙂) Until recently I was totally satisfied with Disk Utility and had stopped buying third party disk utilities programs - I'm beginning to rethink that since, among other things, I hate the newly redesigned partitioning scheme. Whether another program could have mounted and repaired the problem I don't know though.

Note: were it mine, I'd make sure any important files on the drive were backed up elsewhere. That problem might be a one time event - it happens - or it might be a harbinger of more to come...and eventual data loss.

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