My external hard drive is not recognized

I have the apple external disk drive. I have used it numerous times. I just plugged it in and the computer is not recognizing it. I have tried both USB ports. How can I fix this?

A: USB desktop or 2.5" port powered?
B: did you just install mavericks
C: DOES IT show in disk utility?
Can you confirm it on another Mac?
Apple doesnt make HD, what HD is it marked as?
Likely its a dead SATA bridge card, a very very common problem with USB and external HD
see here:
Your dead external hard drive is likely fine! Great hope for your 'faulty' external HD
report back with more info

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My external hard drive is not recognized by my computer.

My external hard drive is not recognized by my computer. I used it earlier and it was fine however my computer froze and I unplugged my hard drive without properly ejecting it. Now when I plug it in nothing pops up. I've tried on three different computers and no luck. I hope this is fixable! Please help.

Care to share which OS you are using?
Repair permissions & restart your computer.
Zap the PRAM

The external hard drive is not recognized by my macbook pro (yosemite).

The external hard drive that was recognized by my older iMac (snow lion), is not recognized by my new macbook pro (yosemite).
Can anyone help me with this? Thank you!

Can you see the drive in Disk Utility?
See mount section in 1st linked article.
Disk Unmount Using Terminal
Disk Utility – Force Mount Disk

External hard drive is not recognized in Migration Assistantt

I had my hard drive replaced on my iMac, Mac OS 10.4.11, Snow Leopard.
I backup my computer using Time Machine onto an external hard drive.
In Migration Assistant, the external hard drive does not show up. There are no choices to choose to migrate from.
Any suggestions please!

See Pondini's TM FAQs, for starters.

External hard drive is not recognized after attempt to format

I just got a new macbook and couldn't use my external hard drive because it was formatted on a PC and only allowed me to read the data. I backed up the data on the 250gb hd and then used Disk Utility to erase the hd and format it as "Mac OS extended (journaled)." After beginning, Disk Utility stopped working and showed up as "not responding" in the Activity Monitor.
Now the hd does not show up on the desktop and can only be seen in Disk Utility. If I try to erase again or partition the hd the utility stops responding. If I try to zero out the drive it continues to say "preparing to zero" indefinately. Now the hd is also not recognized by windows except in the windows disk utility, but it does not even give the option of formatting/initializing it, so that is not an option.
Has anyone ever seen anything like this before, or have any idea of something that I haven't tried yet. I really want to get the drive working and have exhausted all the ideas I can come up with. The internet has not provided too many ideas either.
Thanks so much for your help.
Black MacBook Mac OS X (10.4.6)

I have crazy solution to format it to FAT 32, it work a couple times on my several MAxtor, and Western Digital HD. But this is the last resort and if you are not handy and familiar, don't do it.
It happen on my external HD, so I crack the enclosure open, pulled the HD out and attached it as internal HD on a PC after adjusting the jumper to master and make sure no other HD attached to the motherboard. Make sure the motherboard detected (you can see it from bios menu).
Insert a bootable installer disk before XP ('98, ME, or 2000), and start from there until a promt comes, and type fdisk and you delete the old partition and create a new partition and restart once using the disk still and format it using FAT 32.
After that you put it back to the enclosure, and mount it to MacBook as a new HD with default factory format.
If you don't have the installer disk, this might help :
http://www.bootdisk.com/
But if your maxtor still under warranty better talk to them first and they might willing to reformat it for you.
Hope this help your external back and let you use it on your MacBook.

External Hard Drive suddenly not recognized

I have a WD 500GB external hard drive that I use to back up my data. I only have one hard drive as I'm currently living abroad and couldn't bring a 2nd with me.
I plugged in my external last night to back up my MacBook Pro and it backed everything up. I even went into Time Machine to go back and restore a file or two and that worked without problem. I have been using this drive for about a year to back up everything on my Mac and, although sensitive, it seems to work okay.
I plugged it in this morning and nothing. My Mac will not recognize that the drive is not plugged in in Time Machine or in Finder. If I go to Apple Logo > About This Mac > More Info... > Storage tab, it just shows my internal hard drive and my CD/DVD drive. If I click on Disk Utility with the drive plugged in, it shows my Hard Drive (Macintosh HD) with two icons, one inset below the other and both in black font, and then my external hard drive has two underneath, but only the top one is black font - the one underneath is greyed out.
It goes like this:
250.06 GB Hitachi...
     Macintosh HD
500.08 GB WD My Passport
     Time Machine Backups (greyed out)
Superdrive (greyed out)
When I clicked on the 500GB one and told it to repair/verify it said the disk was working fine. I tried unplugging and replugging in the drive (it is not recognized in Finder so I could not properly eject the disk). I restarted my Mac with it unplugged and plugged it in afterward and nothing.
The HD itself is working, the light is blinking (not solid) and I can feel the hard drive spinning, but I'm at a loss as to what to do to get my Mac to recognize it again.
Any suggestions would be helpful.
Thank you!

I also wanted to add, when I click on the greyed out Time Machine hard drive that's listed and then click "Info", this is what it says:
Name : Time Machine Backups
Type :           Partition
          Disk Identifier :           disk1s2
          Mount Point :           Not mounted
          File System :           Mac OS Extended (Journaled)
          Connection Bus :           USB
          Device Tree :           IODeviceTree:/PCI0@0/EHC2@6,1
          Writable :           Yes
          Universal Unique Identifier :           56EF6088-FFCE-300B-81D7-3E0986532AB5
          Capacity :           499.74 GB (499,735,552,000 Bytes)
          Owners Enabled :           No
          Can Turn Owners Off :           Yes
          Can Be Formatted :           Yes
          Bootable :           Yes
          Supports Journaling :           Yes
          Journaled :           No
          Disk Number :           1
          Partition Number :           2

My Passport for Mac external Hard drive is not recognized

I recently had to purchase a new MacBook Pro, and when I tried to get files off of my Passport for Mac external hard drive. I get an error stating "The disk you inserted was not readable by this computer." And when I try to initalize, and verify disk, I get this message "Partition map check failed because no slices were found.". I have already updated firmware for the external hard drive. One site I found stated that it could be that the USB port is not strong enough, and I would need a 2.0 Booster cable. Does anyone know if this would work?

What did you old Macbook die from? Likely the HD in it is still ok, yes?
You can remove the HD inside your old dead Mac and put it into a $20 HD enclosure or HD dock, and remove the photos that way, very easy.........IF your old Macbook died from something other than ALSO a bad HD.
You said----my OLD Macbook pro which recently lost video
What happened with your old "dead" macbook? Still have it?

External hard drive is not recognized anymore

For a couple of months i have been backing up my stuff on an external hard drive (Verbatim) no probs.
Last time I didn't close the external hard drive down properly. Now my Macbook does not recognize the external HD any more.
I have tested the external HD on other PC and it still works fine.
How can I change my settings or do something else to have my Macbook recognize is it again.
Thanks!

Whenever an external drive is disconnected without first being ejected or dismounted, file system corruption is a very real, perhaps even likely, possibility. If that has happened you might try repairing it with Disk Warrior:http://www.alsoft.com/diskwarrior/
Message was edited by: macbig

My external hard drive suddenly not recognized (retina macbook pro)

Windows 8 has a great feature which is "windows to go", so I have installed windows 8 in my external hard drive. The problem just happened. I was using windows via my hard drive. I shut down the computer and turned on mac system. Then the hard drive wasn't detected!
I have tried doing following things but didn't work:
I plugged out and plugged in the the external hard drive again.
I restarted the mac system.
I put my charger on.
I opened the console and here are the "Message"...:
1/18/14 8:53:51.000 AM kernel[0]: USBMSC Identifier (non-unique): 012345678933 0x152d 0x539 0x1302, 3
1/18/14 8:53:52.000 AM kernel[0]: MacAuthEvent en0   Auth result for: 10:bf:48:3d:cb:03 Auth request tx failed
1/18/14 8:54:39.000 AM kernel[0]: MacAuthEvent en0   Auth result for: 10:bf:48:3d:cb:03 Auth request tx failed
1/18/14 8:57:13.000 AM kernel[0]: MacAuthEvent en0   Auth result for: 10:bf:48:3d:cb:03 Auth request tx failed
PLEASE HELP ME!

It is formatted for both PC and Mac
I have tried finding it in Disk Utility, no dice...
Tried both USB Ports
And a reboot is still unsuccessful..

My external hard drive is not recognized by Time Machine; "The backup disk is not available" according to Disk Utility

I'm not completely tech savvy, but I'm having troubles with my external memory & time machine. I'm a student, and thus its very important to me to be able to back up my computer.
I wanted to back up my Time Machine the other day. I clicked the icon at the top of the page (beside the battery icon, etc.) and the message "The backup disk is not available". I have a 500GB Seagate passport (ie: http://www.bestbuy.com/site/Seagate---FreeAgent-GoFlex-500GB-External-USB-2.0-Po rtable-Hard-Drive---Silver/9929098.p?id=1218196478444&skuId=9929098)
My macbook pro is version 10.7.5 Mac OS X Lion. My external memory is only about a year old. It hasn't been dropped or anything; it permanently sits secured to my desk.
What appears when I click "Repair Disk":
Verify and Repair volume “Time Machine Backups”
Checking file systemChecking Journaled HFS Plus volume.
Detected a case-sensitive volume.
Checking extents overflow file.
Checking catalog file.
Incorrect block count for file shutdown_time
(It should be 1 instead of 0)
Invalid node structure
Rebuilding catalog B-tree.
The volume Time Machine Backups could not be repaired.
Volume repair complete.Updating boot support partitions for the volume as required.Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.
After clicking "Repair Disk" this message pops up: "Disk Utility Stopped Repairing 'Time Machine Backups' Disk utility can't repair this disk. Back up as many as your files as possible, reformat the disk, and restore your backed-up files."
I don't want to wipe my memory on my external disk just in case the disk doesn't restore (as I do not have another disk to back up my computer on to).
What is going on? Why is this happening out of the blue? How can I fix this?

Sounds like it either has, or is about to die.
If you don't need anything off the old drive, then yes, replace it immediately with something a little more reolaable. I use WD Caviar Black personally. But anything that has a known low failure rate.

My external hard drive is not recognized on my new MacBook Pro, even though it is recognized on my older MacBook and other computers. Help?

Please help me find a solution to my new MacBook Pro not recognizing my hard drives. Yes, thats two hard drives I have that don't seem to work on this computer but both work on my older MacBook and many other computers.

It is formatted for both PC and Mac
I have tried finding it in Disk Utility, no dice...
Tried both USB Ports
And a reboot is still unsuccessful..

WD 4TB External hard drive is not recognized by T410

Hi All,
I have a 4 TB hard drive that I use to back up my office PC. I have memory to backup my T410. When I plugged it, there the laptop recognized that there is a new device and tried to find the proper driver for it. Unfortunately it didn't recognize it and it.
My os is windows 7 - 64 bit.
Is this an issue with the T410 ? is there a way to resolve this problem ?
Cheers
Zeyad
Solved!
Go to Solution.

I found the problem. The issues was that windows didn't download the correct driver. I was checking under Computer management - Storage and couldn't find the drive. When I checked under devices and printers I found the hard drive attached by not functional. So I simply looked for the proper driver and the issue is solved.
thanks richk for your response.

Satellite C50-D - External Hard Drive is not recognized

Have just purchased Satellite C50 D but cannot get it to read or recognise my LaCie hard drive.
As this has all the data from my previous computer it is rather important. Can anyone provide help and guidance as to how to a) read the drive or b) transfer all the data onto the laptop memory
Many thanks
A:-)

Hi
The notebook supports 1 USB 3.0 port and 2 USB 2.0 ports.
I recommend you to connect the external HDD to each port (USB2.0 and USB3.0) just to check if its not compatibility problem. But usually it should not be a big problem to connect an external USB 2.0 device to an USB 3.0 port.
However, it could be also possible that this external HDD needs more than usual 500mA power provided by one USB 2.0 port. In such case you should use an USB Y cable to connect the HDD to two USB ports.

Portable external hard drive (500gb) not recognized on computer

I have been using a portable hard drive to backup all my files for some time. I plug it in now and the led light briefly flashes and then , nothing. Computer does not recognize it anymore. I really need these files! any suggestions?

Oms2208 wrote:
I have been using a portable hard drive to backup all my files for some time. I plug it in now and the led light briefly flashes and then , nothing. Computer does not recognize it anymore. I really need these files! any suggestions?
what computer? please provide full model number. it is printed on back
L305-S5955, T9300 Intel Core 2 Duo, 4GB RAM, 60GB SSD, Win 7 Ultimate 64-bit

External hard drive volumes not recognized as startup disks

Using "option" at startup only yields Mac HD not external drive volumes.

By your description, it doesn't look like the OS's installed on the partitions are capable of booting your machine. If they don't qualify for your machine, they will not show up in a list you can choose from.
Your machine has a minimum OS that it will support, as of the day it was made. I assume that since you are posting in a Snow Leopard forum that your machine has an intel processor. The iBook G4 does not, and the Mac mini OS may be too old of a version of OS X to run on your machine.

My external hard drive is not recognized

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