Time Machine external hard drive not recognized

I connected an Iomega Ultramax 500GB Hard Drive to my imac to set up time machine. It has worked well for years but now has disappeared and time machine no longer backs up to the hard drive. The drive is recognized in the system profiler and I have tried Repair Disk with the Disk Utility but get the message:
Invalid record count
Volume check failed
Error: Filesystem verify or repair failed.
Can someone give me some guidance? Thanks!

If you don't have backups, and the drive doesn't work, you may have lost all the data. There are ways to try to recover data from a failed drive, but I have no experience with that and can't help. If the data is valuable to you, your best chance is to send the drive to a data-recovery service such as DriveSavers, but that will be very expensive.

Similar Messages

Time Machine & external hard drives not used daily

I have a question about Time Machine and external hard drives that I used for storing digital files. I do not need to turn on these drives every day. Or even every week. Is Time Machine going to "forget" them (delete their files from backups) if I don't turn them on regularly? What do I do to make sure they are safely backed up and that they stay backed up even if they aren't turned on every day?

As I said, then, "Time Machine will simply pick up wherever it left off." Just be sure to properly eject the drive before disconnecting or shutting off.
The "speed" question is a new one not present in your original post. You can address that in the following:
Kappy's Personal Suggestions About Mac Maintenance
For disk repairs use Disk Utility. For situations DU cannot handle the best third-party utility is: Disk Warrior; DW only fixes problems with the disk directory, but most disk problems are caused by directory corruption. Drive Genius provides additional tools not found in Disk Warrior for defragmentation of older drives, disk repair, disk scans, formatting, partitioning, disk copy, and benchmarking.
Four outstanding sources of information on Mac maintenance are:
1. OS X Maintenance - MacAttorney.
2. Mac maintenance Quick Assist
3. Maintaining Mac OS X
4. Mac Maintenance Guide
Periodic Maintenance
OS X performs certain maintenance functions that are scheduled to occur on a daily, weekly, or monthly period. The maintenance scripts run in the early AM only if the computer is turned on 24/7 (no sleep.) See Mac OS X- About background maintenance tasks. If you are running Leopard or later these tasks are run automatically, so there is no need to use any third-party software to force running these tasks.
If you are using a pre-Leopard version of OS X, then an excellent solution is to download and install a shareware utility such as Macaroni, JAW PseudoAnacron, or Anacron that will automate the maintenance activity regardless of whether the computer is turned off or asleep. Dependence upon third-party utilities to run the periodic maintenance scripts was significantly reduced after Tiger. (These utilities have limited or no functionality with Snow Leopard, Lion, or Mountain Lion and should not be installed.)
Defragmentation
OS X automatically defragments files less than 20 MBs in size, so unless you have a disk full of very large files there's little need for defragmenting the hard drive except when trying to install Boot Camp on a fragmented drive. But you don't need to buy third-party software. All you need is a spare external hard drive and Carbon Copy Cloner.
Cheap and Easy Defragmentation
You will have to backup your OS X partition to an external drive, boot from the external drive, use Disk Utility to repartition and reformat your hard drive back to a single volume, then restore your backup to the internal hard drive. You will use Carbon Copy Cloner to create the backup and to restore it.
1. Get an empty external hard drive and clone your internal drive to the
       external one.
2. Boot from the external hard drive.
3. Erase the internal hard drive.
4. Restore the external clone to the internal hard drive.
Clone the internal drive to the external drive
1. Open Carbon Copy Cloner.
2. Select the Source volume from the left side dropdown menu.
3. Select the Destination volume from the left side dropdown menu.
4. Be sure the Block Copy button is not depressed or is ghosted.
5. Click on the Clone button.
Destination means the external backup drive. Source means the internal startup drive.
Restart the computer and after the chime press and hold down the OPTION key until the boot manager appears. Select the icon for the external drive and click on the upward pointing arrow button.
After startup do the following:
Erase internal hard drive
1. Open Disk Utility in your Utilities folder.
2. After DU loads select your internal hard drive (this is the entry with the
       mfgr.'s ID and size) from the left side list. Note the SMART status of the
       drive in DU's status area. If it does not say "Verified" then the drive is
       failing or has failed and will need replacing. SMART info will not be
       reported on external drives. Otherwise, click on the Partition tab in the
       DU main window.
3. Under the Volume Scheme heading set the number of partitions from the
       drop down menu to one. Set the format type to Mac OS Extended
       (Journaled.) Click on the Options button, set the partition scheme to
       GUID then click on the OK button. Click on the Partition button and wait
       until the process has completed.
Restore the clone to the internal hard drive
1. Open Carbon Copy Cloner.
2. Select the Source volume from the left side dropdown menu.
3. Select the Destination volume from the left side dropdown menu.
4. Be sure the Block Copy button is not selected or is ghosted.
5. Click on the Clone button.
Destination means the internal hard drive. Source means the external startup drive.
Note that the Source and Destination drives are swapped for this last procedure.
Malware Protection
As for malware protection there are few if any such animals affecting OS X. Starting with Lion, Apple has included built-in malware protection that is automatically updated as necessary. To assure proper protection, update your system software when Apple releases new OS X updates for your computer.
Helpful Links Regarding Malware Protection:
1. Mac Malware Guide.
2. Detecting and avoiding malware and spyware
3. Macintosh Virus Guide
For general anti-virus protection I recommend only using ClamXav, but it is not necessary if you are keeping your computer's operating system software up to date. You should avoid any other third-party software advertised as providing anti-malware/virus protection. They are not required and could cause the performance of your computer to drop.
Cache Clearing
I recommend downloading a utility such as TinkerTool System, OnyX 2.4.3, Mountain Lion Cache Cleaner 7.0.9, Maintenance 1.6.8, or Cocktail 5.1.1 that you can use for periodic maintenance such as removing old log files and archives, clearing caches, etc. Corrupted cache files can cause slowness, kernel panics, and other issues. Although this is not a frequent nor a recurring problem, when it does happen there are tools such as those above to fix the problem.
If you are using Snow Leopard or earlier, then for emergency cleaning install the freeware utility Applejack. If you cannot start up in OS X, you may be able to start in single-user mode from which you can run Applejack to do a whole set of repair and maintenance routines from the command line. Note that AppleJack 1.5 is required for Leopard. AppleJack 1.6 is compatible with Snow Leopard. (AppleJack works with Snow Leopard or earlier.)
Installing System Updates or Upgrades
Repair the hard drive and permissions beforehand.
Update your backups in case an update goes bad.
Backup and Restore
Having a backup and restore strategy is one of the most important things you can do to maintain your computer. Get an external Firewire drive at least equal in size to the internal hard drive and make (and maintain) a bootable clone/backup. You can make a bootable clone using the Restore option of Disk Utility. You can also make and maintain clones with good backup software. You can never have too many backups. Don't rely on just one. Make several using different backup utilities. My personal recommendations are (order is not significant):
     1. Carbon Copy Cloner
     2. Get Backup
     3. Deja Vu
     4. SuperDuper!
     5. Synk Pro
     6. Tri-Backup
Visit The XLab FAQs and read the FAQs on maintenance and backup and restore.
Always have a current backup before performing any system updates or upgrades.
Final Suggestions
Be sure you have an adequate amount of RAM installed for the number of applications you run concurrently. Be sure you leave a minimum of 10% of the hard drive's capacity or 20 GBs, whichever is greater, as free space. Avoid installing utilities that rely on Haxies, SIMBL, or that alter the OS appearance, add features you will rarely if ever need, etc. The more extras you install the greater the probability of having problems. If you install software be sure you know how to uninstall it. Avoid installing multiple new software at the same time. Install one at a time and use it for a while to be sure it's compatible.
Additional reading may be found in:
1. Mac OS X speed FAQ
2. Speeding up Macs
3. Macintosh OS X Routine Maintenance
4. Essential Mac Maintenance: Get set up
5. Essential Mac Maintenance: Rev up your routines
6. Five Mac maintenance myths
7. How to Speed up Macs
8. Myths of required versus not required maintenance for Mac OS X
Referenced software can be found at CNet Downloads or MacUpdate.
Most if not all maintenance is for troubleshooting problems. If your computer is running OK, then there isn't really a thing you need to do except repair the hard drive and permissions before installing any new system updates.

Time Machine External Hard Drive not visible

I use a hard disc attached to a new mac mini (2014) for my time machine backups. I have an apple airport extreme base station. I have two macbook pros on the network. One of the machines accesses the hard drive attached to the mini with no problems when doing a time machine back up.
The other does not see or recognize the hard disc. The only icon available in the time machine preferences is a generic "Other Time Capsule."
I have tried all the suggestions found here, OS X Mountain Lion: If Time Machine can’t find your backup disk, with no luck.
I have also gone to the library preferences and deleted the preference file for time machine. Again no luck.
The macbook pro that cannot access the hard disc used for time machine back ups is running the latest Mac OS (10.9.4).
I'm stumped. Any ideas? Thank you.

See Pondini's TM FAQs.
iMac refurb (27-inch Mid 2011), OS X Mavericks (10.9.4), SL & ML, G4 450 MP w/Leopard, 9.2.2

Time Machine- external hard drive not appearing

I'm trying to set up Time Machine. However, the Maxtor one touch 4 plus drive is not appearing as an option to choose to set as back up drive?
Any suggestions?

Make sure it's not formatted as FAT32?

Time machine external hard drive requires repair every time I turned the computer off or after I ejected the external hard drive?

Time machine external hard drive requires repair every time I turned the computer off or after I ejected the external hard drive?

What kind of repair?

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

Time machine external hard drive in windows not working.

I recently bought a Western Digital external hard drive to use with time machine so that I would have my laptop backed up. When I set up the time machine, it had to format my hard drive, erasing the WD files that were on the drive. I was able to continue using it as an external storage device on the Mac side of my laptop, but when trying to use it on the windows side, it wont show up in My Computer. I'm starting to wonder if I will be unable to use this external drive on anything other than a Mac now that it is set up as my Time Machine.
If that is the case, is there a way that I can reset my drive to not show up as my Time Machine Disk.
Thanks,
JT

If you're going to use the drive on both platforms, does it need to be set up first on the PC, allocating 1/2? to Windows NTFS format, then disable/reset/delete Time Machine backups doing the Mac HFS format thing on remainder of External?
Setup on my Acomdata 7200rpm External is Mac 150GB HFS, Windows 150GB NTFS. On Windows side, is Vista, W7 (32 &64Bit) and recently my daughter's HP Laptop XP which posed a problem until I found that NtBackup.Msi was in VALUEADD folder on the Windows XP install CD. Also available from Microsoft if no install CD. NtBackup makes a .BKF string of the hard drive, runs maybe a little slower than Vista & Windows 7 Backup/Restore Maint. Long time since I restore a .BKF but think it requires an OS - unlike Vista + Windows 7 where the install Disk will retore from External in ~30 minutes.
I have not figured out how to get Leopard restored short of format, then complete (re)install with Time Machine restore kicking in at the end of that process. Takes a great deal of time and some things need fixing after completion. Wondering if Snow Leopard/Disk Utility has any improvements on this score. Refuse to pay for anything that I consider to be intrisically necessary to use of product.

I just had my hard drive replaced and restored everything from a Time Machine external hard drive backup and now my "note" widgets won't load. Any ideas ?

I just had my hard drive replaced. I restored it using a Time Machine backup on an external hard drive. When I open Dashboard none of my "note" widgets will load. The other widgets open, such as weather, weather radar, calculater, dictionary, stock... Even the iPhoto Mini widget works, just not the notes ( Sticky Notes and K-Notes ). Any ideas on how to fix this ?

I did some research and found the solution to my problem. So I hope it's okay to answer my own question.
When you reinstall the OS, your Preferences go back to their default settings. Apparently Preferences is where this widget information is stored. This Preferences folder is located in the user Library folder which is hidden by default. You can access it using "one, or the other" of the following actions.
Action 1:      (1) In the Finder, choose Go > Go To Folder
                     (2) In the Go To Folder dialog, type ~/Library
                     (3) Click Go
                                                      -- OR --
Action 2:     Hold down the option (alt) key when using the Go menu. The Library folder is listed just                            below the Home folder.
After opening the Preferences folder, the file that you want to locate for k-notes is named
widget-com.rakoth.lichlord.widget.k-notes.plist
After you locate it make note of the byte size of the file. Now, with the Preferences folder still open, open Time Machine and go back in time until you see a big jump in the file size. That will be your uncorrupted plist. Restore it and close Time Machine.
Then Restart your computer.
After following this procedure I brought up Dashboard and my blank k-notes were now refilled with the previous text and color that occupied them before I had to restore the OS.
This procedure also worked for Sticky notes, which in the Preference folder are named
widget-com.apple.widget.stickies.plist

My Time Machine external hard drive is not recognised anymore under 10.9.1

Hi,
I am running 10.9.1 on my MBP13" mid 2010.
I plugged in my external hard drive (Western Digital Elements 500GB portable drive) and it is no longer recognised.
This has been going on for a couple of weeks.
TM says its not connected.
Icon not on desktop
not seen in disk utilities.
I have tried it on another machine (iMac 2006 10.6) and it is not recognised either.
Tried rebooting with the drive plugged in and without.
attempted to install WD Quick Formatter and this saw the drive but was unable to reformat as it said that it was 'in use'
I thought that this might be TM so I disassociated it from TM - Still No Go.
Any Ideas appreciated.

katlandsf wrote:
I have a 750gb hard drive that Time Machine backs up on. It's been for going strong for over 2 years now. My hard drive is filling up, I only have 35gb left. Is it okay for me to delete many of the old backups dated from 2 years ago? I really only need to keep the last 6-12 months. Not sure how to handle this.
You don't have to do anything.
When Time Machine is out of room, it will automatically delete the oldest backup(s) to make room for new ones. If you have the +Notify after old backups are deleted+ box checked in Time Machine Preferences > Options, you'll see the message in the blue box in #C4 of [Time Machine - Troubleshooting|http://web.me.com/pondini/Time_Machine/Troubleshooting.html] (or use the link in *User Tips* at the top of this forum).
If you do want to manually delete some backups, you can do that, but only via Time Machine. See #12 in [Time Machine - Frequently Asked Questions|http://web.me.com/pondini/Time_Machine/FAQ.html] (or use the link in *User Tips* at the top of this forum).

Firewire thunderbolt adaptor does not recognize my time machine external hard drive

Hi everybody. I have a retina MacBook Pro, and wanted to connect my time machine external HD to the mac using a firewire-thunderbolt adaptor.
I did so, but the HD does not show up in the devices menu. Any suggestion?
thank you for your help
Giulio

Have you tried rebooting? If you share what type drive you have, perhaps others will share their experiences. Is your drive bus powered? I haven't had any trouble so far connecting through a TB-FW adapter to my external hard drive (Hitachi drive in an OWC case, bus powered).

How to create mirror backup of my Time Machine external hard drive

I am running Time Machine back ups for my MacPro with OS 10.8.5, purchased in 2008. I am saving the Time Machine back ups to an OWC Mercury Elite-AL Pro 2TB external hard drive. I have a second 2TB external hard drive and would like to mirror what's backing up to the first 2TB external hard drive. I feel that it gives me better odds if I plug the hard drive in one day and it isn't recognized, or some calamity happens to my computer and everything goes downhill from there, which seems to be the rule rather than the exception. Currently I store the external hard drives in a safe in my home between uses. They don't spend 24/7 hooked to my computer.
I would like to know that I always have two copies of the same Time Machine back up on hand.
Thanks,

Drives fail. Often in the first six months, and after that, they may last 5-6 years. Or not. A weak (not just bad) sector block is usually the best indication. Having spare drives on hand should be a must, and rotate primary drives to backup or archive every two years maybe after giving them a long erase - to ease your fears and hopefully find the worst possible error.
RAID6 is useful for holding large video catalogues and projects - and then mirror your RAID6 to another RAID6.
SoftRAID 5 http://www.softraid.com will scan drives in the background for weak blocks, monitor I/O better for read/write errors (without impacting performance is important) and can be well worth its $140 ish price (worth it in tech support alone, too if ever you need it)
A couple programs will write the SMART status to the system log and show the numbers of used and remaining spare blocks. That is something a large study of disk storage revealed. And in today's world, storage needs and the need to "change the light blubs" on a basis before one fails is a must in massive data cloud and big data mining.
Apple's Mac Pro and the RAID card is not "hot swap" capable, though the motherboard in the Classic Mac Pro actually could as designed by Intel. And hot swapping is a handy feature - create a 3 drive mirror array, pull one, you still have two and let SoftRAID do a better rebuild in the background adding a new 3rd mirror drive.
Two drive mirrors are weak and not all that great, in my estimation.
TimeMachine is there to get people to at least have a automatic ish do it and forget it, hopefully, versus none at all. A good beginning. It also turns 8 this September and has slowly, gradually, hopefully, matured. I might buy Disk Warrior 5 if only to check the backup catalogue for integrity though at $99 a waste for most and better spent on another backup drive or something. But you never want to be in need of Data Rescue 4, another $99 product.

How to stop my Time Machine external hard drive preventing iMac from sleeping?

I have a late 2012 iMac, and have discovered that sometimes (I haven't noticed a pattern of when it doesn/doesn't happen) the computer will immediately wake up after I set it to Sleep (Apple Menu>Sleep). Through elimination I have found that it is the the USB 3.0 external hard drive I use as a Time Machine back-up that is the culprit; unplugging it then allows the computer to sleep. If I unplug it, then plug it back in later on, this normally solves the problem for a while, but not forever. This same Hard Drive didn't cause the wake problem on my previous '08 iMac.
A big issue is that when the machine immediately wakes from sleep, the display stays off (until I move the mouse) - this is good from a power saving point of view, but means I don't know if/when the machine is immediately waking from sleep (I have to listen to the fan when setting it to Sleep mode to hear if it has actually woken back up).
I've searched the forums, but can't find another poster with the same problem as myself. Can anyone advise a course for me to pursue to prevent this from happening?
Thanks. Jamie

Hi Frank. Nope, I'm still having the same symptoms; the plugged in external drive (TIme Machine) will wake the machine up a couple of seconds after it winding down when put to into sleep mode. Ejecting the drive and then sleeping the machine works. After plugging it in again to do a Time machine backup, it will allow the computer to sleep soundly for the first few sessions (eg a few days of sleeping, waking, sleeping, waking, etc), but then it will then suddenly start preventing it from sleeping again after a while.
It seems I'm fortunate in my case that the display stays dark (or off?) when the machine has been woken from sleep, but this was actually preventing me from knowing the machine wasn't in fact asleep for quite some time; I only eventually cottoned on because there wasn't any delay when 'waking' my machine (which there normally is). I would then have to carefully listen to the spinning fans to know if in fact it had gone to sleep or not.
So, to summarise, unfortunately no, I haven't solved this yet. If anyone else has a solution, please let us know?
Also, I've noticed occasionally after waking that there is a relatively quiet 'crackle' sound (kind of electrical sounding) from the bottom-right area of the machine. This goes on every so often for about 30mins. I see this is also an issue with other people's late 2012 iMacs, but I've not seen if anyone has a solution to it?

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.

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

Time Machine external hard drive not recognized

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