External hard drives not recognized by imac

I am a new Mac user and have been having lots of trouble getting my external hard drives to mount. I have a simpletech and a seagate external hard drive both NFTS formatted neither of which is recognized by my iMac. They don't show up on disk utility or system profiier under USB ports. They both work on my PC laptop and a friends iMac (OS 10.6.4) just fine. I have a card reader and flash drive that work perfectly on my iMac. Apple support orginally thought it might be the logic board so they replaced it. The new one is having the exact same problem. Does anyone have any idea what could possibly be the problem?? This is driving me insane.

I'm having exactly the same problem with a new iMac purchased one week ago. I have two Maxtor drives and one WD, all firewire 400 drives, all of which mount briefly and then unmount and will not mount again. I am not new to Macs. The drives work fine on the older PowerPC Mac running 10.4.11. These drives contain my backups and aren't recognized by the new iMac. I cannot believe that 3 external drives are all going into failure mode at the same time since they were all purchased at different times and only used as backup drives, so they weren't on all of the time. Is there an incompatibility between 800 and 400?? I'm using a LaCie 800 to 400 firewire cable. Suggestions??

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External USB Hard Drive not recognized on iMac HELP!!

I am currently using a i5 iMac running Lion 10.7.5
I have recently partitioned a Verbatim USB external hard drive and uploaded all my footage from a wedding. This was done with no problems and the QT videos could be opened from the hard drive.
A few weeks later, the hard drive does not show up in my finder. BUT it is recognized in disk utility. Here is a screen shot;
So first I ran "Verify" and it told me to repair disk. After clicking on Repair, I got this;
It is giving me the error message "Invalid B-Tree node"
Here is more info on the hard drive;
Name : Hitachi HTS545032B9A300 Media
          Type :           Disk
          Partition Map Scheme :           Master Boot Record
          Disk Identifier :           disk1
          Media Name :           Hitachi HTS545032B9A300 Media
          Media Type :           Generic
          Connection Bus :           USB
          USB Serial Number :           091004B3066D
          Device Tree :           IODeviceTree:/PCI0@0/EHC2@1A,7
          Writable :           Yes
          Ejectable :           Yes
          Location :           External
          Total Capacity :           320.07 GB (320,072,933,376 Bytes)
          Disk Number :           1
          Partition Number :           0
          S.M.A.R.T. Status :           Not Supported
Can someone give me a step by step on how to get the hard drive working again? It would mean the world to me as this footage is priceless and irreplaceable.
OR can you refer me to someone (Geek Squad? Apple Store?) that might be able to help me out?
Thanks in advance!

The error message invalid b-tree node size indicates that the directory on the disk is corrupt. The way that it can be repaired is to reformat as disk utiltiy says.
It is recommended that the data be backed up first before either of this solution are done.
Since it is not be recognized by the sytem at all it does sound like you can back it up now.
Do you have a backup?
If you don't there is every chance you may lose all your data.
You can check to see if a data recovery service can recover any data for you. If you go that route you are looking at spending $$$$
Allan

External Hard Drive not recognized.

Hello everyone,
I have a probem where my external hard drive is not being recognized by my late 2009 iMac.
The hard drive is an OWC Mercury Elite-AL Pro connected to the firewire port.
It was working fine till this happenend:
I keep all of my iTuned music on the external hard drive.
I was using a meta tag fixer type program.
I dragged the files from itunes into this program (Tune Up) to fix the meta tags.
However, I missed the program and dragged thusands of .mp3 files onto my desktop.
My computer, of course, became unresponsive.
So I used the power button on the back of the iMac to shut it off.
I used my MacBookPro to connect to my iMac as a target drive, and deleted all the .mp3's from the desktop there.
Once I restarted my iMac everything was fine, except that the external hard drive has not been able to be recognised ever since.
The same drive shows up just fine on my MacBookPro.
Help!
Thanks!

I had the exact same problem! I had to force shut down my iMac (24in, Mid 2007) due to a system freeze. After restarting, everything was working fine, except for my external 1GB G-Drive, which was connected through FW800 port.
The drive connected fine to my MacBook Pro, but it would not be recognized by my iMac. I tried restarting, but neither Disk Utility, nor System profiler would see the drive.
What worked though, was Resetting the System Management Controller (SMC):
1.          Shut down the computer.
2.          Unplug the computer's power cord.
3.          Wait fifteen seconds.
4.          Attach the computer's power cord.
5.          Wait five seconds, then press the power button to turn on the computer.
The drive mounts fine now. I am surprised this is not mentioned by Apple in their support documents! It has happened twice to me and it was the only thing worked both times. The link for the resetting the SMC is here:
http://support.apple.com/kb/HT3964?viewlocale=en_US&locale=en_US
Hope this helps solve your problem too.

Panther crashed now external hard drive not recognized

I was away and a person that lives where I work on my computer set up his computer right next to my G4 iMac. When I looked at the screen it was trying to boot into start up mode but wasnt making it. I firgure it must have been caused by all the pluging and unpluggung.
I tried the resart disk but still has problems, so I reinstalled 10.3.9 al over again. Now its working but it doesnt reognize my external Lacie hard drive.
Ive tried restarting a cople of times, I cant firgure out what could be the trick.
Has anyone any ideas?
iMac Mac OS X (10.3.9)
iMac Mac OS X (10.3.6)
Mac OS X (10.3.6)

I would try the Combo; it's worth a try!
I don't know if the following will help with your issue , since it shows up in Safe Boot, but here it is.....
External hard drive spontaneously unmounted? Try these tips:
NEW FIRMWARE: Try updating your external hard drive's firmware, which is available from your drive manufacturers Web site--or just use VersionTracker's (www.versiontracker.com) search function to find it. Be sure to back up your data before applying the update, and carefully follow the manufacturers instructions.
OUT OF iSIGHT: If you're using an iSight camera while you're using a FireWire drive, the camera may be interfering with the drive's ability to stay mounted. Try temporarily disconnecting your iSight and moving it to a separate FireWire port. If you have multiple FireWire devices, try using a FireWire hub.
POWER PROBLEM: A faulty power adapter could be causing your drive to unmount. Your drive may not be getting enough juice to stay on, causing the drive to turn off and thereby unmounting it from your Mac. Alternately, the power adapter may not be providing a steady amount of power, causing your drive to turn on and off. Try replacing the adapter. If you can't get a replacement adapter from the hard drive manufacturer, try your local electronics store. Just make sure the adapter you choose has the same connector and input/output voltage. you can find the input/output voltage on the adapter itself.
Cheers!
DALE

External hard drive not recognized... help please.

okay, well here is the story:
my iBook G4 had its stock 30gb hard drive in it and it was running extremely low on space. so i figured i didn't want to carry around an external hard drive, therefore i would buy an internal hard drive an install it. so i purchased a new 2.5" 80gb hard drive and called up the local apple store. they told me that although it was under warranty, that it did not cover hard drive installation. so i looked it up online and found step by step instructions to install the hard drive. so after lots of hard work and many screws, i installed the new hard drive successfully... but i still had this perfect 30gb hard drive. i thought maybe to save a few bucks i could turn it into a usb external hard drive. i found an enclosure for the hard drive and a usb 2.0 cable and plugged it into my ibook. it was recognized and everything. i put some files on the external hard drive and transferred it to another mac. this is where the trouble started. i plugged the hard drive into a PowerMac G4, and it was not recognized... so i tried it on a different mac. this time on a PowerBook G4, but no luck. this issue has been troubling me for a few weeks. but then i tried it on a similar iBook G4... and it was recognized. but i don't know why it was only recognized only on the iBook G4 (not the same iBook G4 it was pulled out of) and no other macs.
does anybody have any ideas what we can do to get this hard drive to be recognized by other macs?
any of even the smallest ideas would be greatly appreciated.
thanks,
tyler
iBook G4 Mac OS X (10.4.3)

I can walk you through formatting the hard drive:
1. Hook it up to an iBook that recognizes it.
2. Go into your Applications folder, then scroll down to Utilities. Open Utilities and scroll down a bit and you should see Disk Utility. Double-click.
3. On the left side you should see your internal hard drive and your external one. Each hard drive will have a sub-catagory with the partition indented.
4. Your external hard drive will probably be the second catagory. Click it.
5. In the center-top you should see the tabs First Aid, Erase, Partition, RAID, and Restore. Click the Erase tab.
6. You should see Volume Format: and then a drop down menu, and Name: and a text box. Type in the name you want the external hard drive to be named.
7. In the drop down menu, select Mac OS Extended (Journaled).
8. Then, simply click Erase, watch the progress and it should be good to go!!
Hope I helped you out. Oh, and it might be the enclosure...and also what OS's? Since it's USB it is probably using a USB Mass Storage driver. Mac-wise, if formatting doesn't help, I would get a FireWire enclosure because FireWire is much faster than just USB 2.0. Oh, thats nother thing...Is the enclosure Hi-Speed USB? If it isn't, I would definitely get a FireWire one...If it is, the PowerMac G4 doesn't have Hi-Speed so you're not taking full advantage..Just some insight
iBook G4 Mac OS X (10.4.3) 512 MB Ram, CD-RW Combo Drive, 40 Gig HD, bought in October of 2005...
Message was edited by: Hilary_Rose

Toshiba External Hard Drive not recognized by computer. Please help!

I was wondering if anyone could help me. I have an external hard drive and it will not show up in "My computer" when I plug it in. I have tried other USB drives and other computers. I am starting to think it is a hardware issue but I don't want to lose hope. The blue light is coming on when you plug it in but it doesn't blink and there is no noise whatsoever. Is there anything I can do to fix this issue so that I can recover the information on it? Thanks in advance for any help. It is greatly appreciated.
Additional information: I'm not sure how old this thing is but the model number is HDDR160E03X.

Same problem: I can't see my Toshiba PH3100U-EXB (Gen 2) external hard drive when I plug it in. After awhile I get this error message (see attachment): USB Device Not Recognized. One of the USB devices attached to this computer has malfunctioned, and Windows does not recognize it. FOr assistance in solving this problem, click this message."
When I click it, I get a list of USB ports and devices, with Unknown Device in bold face. No real information there.
Yes, I ran Disk Management and the Toshiba did not show up when I plugged it in and hit Refresh.
Does it make a difference that the last time I used the external hard drive, we were in Windows XP and now we're in Windows 7?
Please help! It's not just the backing up I'm worried about...it's being able to retrieve files later!
Thanks!
Attachments:
USB-NotRecognized.jpg ‏28 KB

External hard drive not recognized in Finder or Disk Utility

Two weeks ago, my 2007 black Macbook stopped recognizing the hard drive. I was told by some IT friends that the controller had likely failed and I needed to purchase a new laptop. I removed the hard drive and placed it into an enclosure (turning it into an external hard drive) and hooked it up to a new Macbook Pro which I purchased a couple days ago. The external hard drive did not show up in Finder or Disk Utility but the light on the enclosure was on and it was making a very soft whirring noise and got warm after a few minutes. I usually backed up the hard drive but, of course, hadn't done it in a couple of weeks before it died so everything I worked on in that time is lost to me at the moment. I'm trying to avoid paying tons of money for a data recovery service so any advice would be greatly appreciated! Thanks!

That whirring noise might be due to physical damage on the disk. I know data recovery services are costly but that remains only the solution for damaged HDD. You can get latest quotes on services from different dealers. Proceed only when your data is very important to be recovered.

Now, USB External Hard Drive Not Recognized after 10.6.8 Update

My external Hard Drive is not recognized on start up. I have to unplug it and plug it back in for it to be recognized.
All this since 10.6.8 updated today.
I'm a fool for updating the same day.
This has happened before and I always forget the bugs in the software when it first comes out.

Alright, I'm gonna go ahead and close this thread. I found out the solution to my issue. Turns out it was a problem with a system file I changed right before installing. The error only occurred on a restart... the required 10.6.1 reboot was the first reboot since the change, so thus it looked like the culprit.
If you want a more thorough explanation of my problem (highly HIGHLY doubt it's gonna help you guys out), check this thread --> http://forums.appleinsider.com/showpost.php?p=1480362&postcount=8
Sorry for the trouble!

Lacie External Hard Drive Not Recognized After It Previously Was

I have a 1 Tb Lacie Big Disk External Hard Drive that I have used for a couple years now. I have a Mac Pro, an iMac and a G5 computer that I have previously used with it. After I transferred it between computers yesterday suddenly it will not show up on any of the computers. I have tried different cables and inputs, computers, other hard drives with the same cables (they worked), restarting the computers, etc. The hard drives powers on like normal and you can hear it running, the blue light comes on in the front, but it never gets the disk loaded on the computer. There is a "auto/on/off" button on the back that I have tried switching between but nothing seems to work. Please let me know if this is a common problem and any way to get it to work as I would prefer not to lose the information on the hard drive, especially when it seems to be functioning just fine aside from not appearing on the computer.

Even backups need backups too.
And a 'good' case is one where you can pulll the drive out and pop it into your Mac pro drive bay.
power supply bricks are known issue.
Mac OS updates that affect those models.
LaCie almost by their own invented the term and idea "reset firewire bus" routine after all.
Years and you can assume not forever but eventually it could and will fail.
I'd pick up a "spare" or replacement unit, one with eSATA/FW800/USB3
http://www.macsales.com/firewire
CallDigit 2 x SATA plus 2 x USB3 $139 - USB3 card and interface works better even on legacy (how long and old is USB2 now?) USB drives.

WD external hard drive not recognized after improper eject

I have a WD Passport external hard drive that I've been using for a while with my MacBook Pro. The cord got yanked, causing the drive to improperly eject. Now my computer isn't recognizing the HD. Help! Of course EVERYTHING important is on this drive!
I tried plugging it into a Mac desktop, which also did not recognize the drive.
I plugged a different Passport into my MacBook Pro, and it was recognized, so I know it's not the USB Port that's causing the problem.
I used the cord from the HD that mounted with the problem HD. Didn't mount with the new cord. So I know it's the passport that's causing the problem, not the MacBook, not the USB port, not the cord.
I ran the disk utility, and the HD does not appear...It is powering up though- the light on the HD is lighting up. Oh please help!
Did I kill my disk? Of course I just moved my entire iPhoto library to this location, and I haven't backed it up yet....

No. It may just require a 00 Phillips driver depending upon the enclosure. Do the swap on a towel so that the little screws don't bounce away from you. You will have to pull the HDD out from the connecting plug. Do it in a straight line,don't bend it, and you may have to slowly increase pressure to get it out of the connecting plug.
It's not rocket science.
Ciao.

External hard drive not recognized by Mavericks?

I have a Western Digital My Passbook 500GB external hard drive connected to my MacBook Pro via USB.
It worked fine until I upgraded to Mavericks. Now it is not recognized at all in my Finder.
When I go to Disk Utility, it finds it and says "not supported". When I do "disk verify" it says it needs to be repaired.
When I try to repair it, it says it can not.
What do I do?

See: http://wdc.com/wdproducts/wdsmartwareupdate/wdsmartware.asp?id=wdfGeneric&os=mac
WD SmartWare update highlights:
Mac release 1.3.6 (updated 11/25/2013)
Fixed an issue related to reports of some customers, under certain conditions, experiencing data loss when updating to Apple's OS X Mavericks (10.9).For more information on this issue, please click here.*Please note that if you have a previous version of WD Drive Manager installed on your computer, this software package will automatically uninstall the old version and install a new version.

External HArd Drive not recognized by MAcBook Air

Hi,
I bought an external hard drive(from LaCie) few months ago and plugged it once to my Macbook Air. I tried to plug it again last month and my MacBook Air didn't recognize it. I also tried to plug it in a PC and not recognized as well.
I've been told to check in the disk utility folder and to format (erase) my hard drive in order to have it running again, but even in the disk utility, hard drive is not recognized.
If anyone had the same problem before, i'd be gratefull of some help.
Many thanks

what lacie hard drive did you buy?
some hard drives require power supplies. if your hard drive requires one make sure it's firmly connect at both ends. If you haven't done so try another outlet. Also some lacie hard drives have a 3 mode switch on the back. make sure it's set to on, if your hard drive has a switch.
Some of the lacies hard drives have a blue button on the front. try another cable. see if the hard drive shows up as a USB device.

External hard drive not recognized with Snow Leopard?

This isn't a new problem, but I finally can't avoid solving it any longer!! When I updated to Snow Leopard, my iMac stopped seeing my LaCie external hard drive (firewire). I've gone through the steps at the LaCie site and checked for updates from Apple, but no luck. I do see an "unknown device" in "About this Mac," but I can't get it to recognize it.
Has this problem been dealt with? Thanks in advance.

monicadale wrote:
I do see an "unknown device" in "About this Mac," but I can't get it to recognize it.
LaCie support is usually excellent, you might give them a call, if you can't find enough on their site.
Look in Disk Utility... is it mounted, or grayed out?
Does it show a volume or not (the indented listing under the drive icon)
If it's not mounted, try choosing it and using the mount icon.
Have you tried reformatting the drive?
Launch/Utilities/Terminal and enter this command at the prompt:diskutil listPress return. Note the number of the disk (far left column) you want to unmount.
Launch/Utilities/Terminal and enter this command at the prompt:
diskutil list
Press return.
If it sees the disk, note the number of the disk (far left column) you want to mount.
Then, enter this command:
mount /dev/(number of disk)
Put in the number without parenthesis.
Press Return.
You may also want to run sudo diskutil repairVolume /dev/(the number of the disk)
Let us know.
-mj

External hard drive not working on iMac

I have a lacie external harddrive that i used on a pc. i am trying to use it on my new iMac but I can't access files or transfer files from the external hard drive to my iMac or vice versa. How can I fix this problem? Should I format it to work on my iMac and if so, will that wipe my external harddrive clean.

The above method may not work with contacts that were created by an older version of the Contacts application.
Triple-click the line below to select it:
~/Library/Application Support/AddressBook
Copy the selected text to the Clipboard (command-C).
Starting from the Finder, locate the snapshot from which you want to restore. Press the key combination shift-command-G. Paste into the text box that opens (command-V) and press return. Select the AddressBook folder in the snapshot, then right-click and select
Restore "AddressBook" to...
from the contextual menu. Choose the Desktop as the location.
Exit Time Machine and open Contacts. From the menu bar, select
File ▹ Import...
Import the file "AddressBook-v22.abcddb" from the folder you created on the Desktop. After importing, you can delete the folder.

External hard drive not recognized after time machine locked up

I was backing up to an external hard drive (300GB Western Digital) and time machine locked up. I had to shut down the computer and restart. Now the external hard drive does not show up on the desktop?
I can see it in disk utility but I am not able to mount or unmount the disk, I keep getting an error that the disk is in use. I tried to erase/reformat the disk and no luck.
Any suggestions?
Thanks for the help

KTM450rider wrote:
Do I need to boot from the install DVD?
this is often the easiest and eliminates any "busy drive" problems. what's wrong with booting from the install DVD? takes a couple of minutes.
My main hard drive is OK... the drive that I am having problems with is an external hard drive that I was using to back up my lap top. I just want to get the external drive reformatted, but disk utility will not erase it. I get an error that disk utility shut down, "please check the drive and make sure that the drive is not in use or programs are still running"
Is their a way to do a hard or forced reformatting of an external hard drive, I don't care about the information on the drive
I also tried disk warrior to recover the info on the disk and all it does is crash my mac pro????
Thanks again for the help

External hard drives not recognized by imac

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