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external hard drive won't mount

by fearlessnellie / February 21, 2010 10:21 AM PST

i'm working with a macbook and I'm having trouble with my external hard drive.
when i connect it, it does not show up on the desktop. it does appear in the side bar of disk utility but it says it is still unmounted and will not let me mount it.
i cannot verify or repair the disk in first aid. nor can i create a new disk image onto another drive.

this has never happened to me before so i am very lost. i've googled my brains out but haven't really found any answers to my specific problem.
this drive has everything important on it so i would really appreciate anything that could possibly help.

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re: external hard drive won't mount
by centurion48 / February 21, 2010 3:11 PM PST

You need to provide more information.
What brand, model & capacity is the hard drive?
Did you previously have this ext HD mounted on any Mac running OS X?
Is the ext HD connected using USB, FW400 or FW800?
Has it ever been mounted while connected to this MacBook?
In the sidebar does it appear under Devices or Shared?
Have you looked at your permissions for the ext HD? Are you even able to get info about the ext HD?
Are you logged in using an Administrator account?


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More info
by fearlessnellie / February 21, 2010 4:34 PM PST

The external HD is a WD My Passport Essential, USB, 250 GB.
I've been using this ext HD for a little over a year, primarily on this MacBook (Mac OS X 10.5.8) that it will not connect to now. It still has about 220 GB of available space.

Everything worked perfectly fine up until last week but now it won't mount. When it would mount, it would show up on the desktop and under Devices.

I am not sure how to determine the permissions for the ext HD.

I am able to get information about the ext HD in Disk Utility. It appears in the sidebar under the Macintosh HD. The ext HD icon appears with "298.1 GB WD 3200BMV External Media" next to it. Underneath that and slightly indented shows the ext HD icon again next to the title of the drive, "Untitled" (because I never formatted it with a title), but it is in faded type.

As this is a personal computer, my account is the Administrator account.

Thanks for helping me out. I didn't even know what questions to ask myself so that I could give adequate information about my problem.
Please let me know if there's anything else I can elaborate on to better diagnose the issue.

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Re: external disk
by Kees Bakker / February 21, 2010 4:45 PM PST
In reply to: More info

- "primarily on this Macbook" means "also on other Mac's" or even "also occasionally on a Windows PC"?
- in what filesystem is it formatted (FAT32 ("MS-DOS"), Mac)?
- does it work on another machine?

Probably it's lost. But if you have a backup, the data isn't lost. That's the most important.


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by fearlessnellie / February 21, 2010 4:57 PM PST
In reply to: Re: external disk

I use it 99% of the time on this Macbook. But I also use it to transfer files to and from my iMac or even less often to and from Macs at school. I have not done this recently though and this has never caused a problem before.

When the ext HD would not mount on my Macbook, I did check to see if it would mount on the iMac but it would not show up on the desktop or the Disk Utility.

It is not formatted to switch from Macs to PCs so therefore I have never connected it to a PC.

It is formatted for a Mac OS X (Journaled).

Unfortunately, I do not have a backup.

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The first thing to do then: ...
by Kees Bakker / February 21, 2010 5:00 PM PST
In reply to: clarification

Try it at school. If it doesn't work there either, it's time to think recovery.

If you read through our Storage forum, you'll find a LOT of posts about external hard disk breaking down. And we ALWAYS stress the need for a backup. Having data ONLY on an external drive is asking to lose it.


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by fearlessnellie / February 21, 2010 5:29 PM PST

I am in total recovery mode. Meaning I'm less concerned about salvaging the hardware and completely concentrated on recovering my files.

I have tried making a new disk image on a separate drive. I have also tried to repair in Disk Utility but it will not work because the ext HD will not mount.

So I'm basically looking for solutions on how to get the external HD to mount again or how to recover files from a drive that won't mount.

Thanks again for all your help.

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Disk Warrior
by mrmacfixit Forum moderator / February 21, 2010 8:51 PM PST
In reply to: Recovery

would be my first attempt at data recovery here.

If the mounting problem is due to a corrupt directory on the disk, Disk Warrior will almost certainly rebuild it.
Even if the drive does not mount on the desktop, DW can usually "see" the drive.

It's available from

It's not free.

Good luck


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Disk Warrior doesn't rebuild ext drives
by Draconius75 / October 23, 2011 2:15 PM PDT
In reply to: Disk Warrior

I don't think so, Disk Warrior only recognises ext and int drives, but can't rebuild external drives, its a useless program for fixing ext drives with corrupted structures.

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by mrmacfixit Forum moderator / October 23, 2011 9:59 PM PDT

Disk Warrior will rebuild both internal and external drives.

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Warrior let's you create a bootable CD
by LaoziSailor / December 10, 2011 3:20 AM PST
In reply to: Wrong,

Warrior let's you create a bootable CD at which point it can rebuild structures on any disk (that is not completely destroyed).
...recover files?, I don't think so and the rebuild may connect all the pointers. Thereafter, backup somewhere, get a second external. If extremely important spend the mula for a RAID1.

Good luck.

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re: mount ext HD
by centurion48 / February 22, 2010 7:15 AM PST
In reply to: Recovery

This document outlines a number of steps you can try. I hope that something in there helps:

Do you always use the same USB port? (Try a different port)
Do you have any other peripherals plugged in at the same time? (Try without them)
Do you always have the ext HD plugged in before you boot up?
Does the WD Passport draw its power through the USB port or does it have a power-brick (If a brick then try another power outlet)


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external hard drive won't mount
by geoffinperth / August 19, 2011 12:25 PM PDT

I get this often using my MBP and WD 1gb via USB.

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I'd worry about a 1GB drive.
by R. Proffitt Forum moderator / August 19, 2011 12:41 PM PDT

These 1GB flash sticks are found for 5 bucks so I'd use that instead and retire any 1GB drives for fear they would fail due to old age.


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by geoffinperth / September 15, 2011 10:03 PM PDT

1tb rather.

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Just a tip.
by R. Proffitt Forum moderator / September 16, 2011 12:45 AM PDT
In reply to: 1tb

Folk don't often repeat the advice inside a discussion. They often do if it's a new discussion. Have you tried all the above?

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