Not recognizing external hard drive

And adding to the woes - my trusty backup external drive suddenly was reported as ejected, but without unmounting. It's no longer recognized by my MB Pro running Mountain Lion, even in Disk Utility. But it is readily recognized by my Mini desktop and Windows laptop. All other external drives are still mounting normally on my MB Pro. It's only this one drive that's a problem - but it contains months of Time Machine backups (along with much video content). It's not a power problem. The drive immediately powers up on the MB. It's not a cable issue either. Partitions and data are intact - I'm still using this drive on my other machines. I'm using a Y usb cable and using both usb connections doesn't make any difference.

I tried rebooting my MB, shutting it down for a while. Tried to wait it out to see if the MB would eventually recognize the drive again. Nada. It's the first and only quirky behavior of my otherwise well-behaved MB Pro (2010 late summer, 13", 4 gigs ram, etc.)

I have the exact same problem.

3 out of 10 times, it won't recognize my ext HD, of course it has to be those times when I'm in a hurry to access important files. Not fun. I took it to Apple yesterday and this is basically what they told me:

https://discussions.apple.com/thread/4822886

Excerpt from customer service call with the a senior manager "It's a machine. It's like buying a car. It breaks down." And I just got mine last December (2012)

😟 😟 😟

If you find a solution, do let me know.

I had same problem and was able to fix it by going to "System Information", looking at "Thunderbolt" connections, ("USB" should work as well), finding my external hard drive in the list, and clicking on it to get more information.

For some reason, that caused my hard drive to mount in Finder.

So... you should at least see if your hard drive shows in "System Information". It's possible that it's there without showing in Finder.

I had this proble; WD 1TB External drive stoped being recognised by my iMac. It was on an external Belkin USB7 Port hub, but even when moved to a USB port on the iMAc still no joy.

In the disc utility, it was recognised so just verified the disc. Seems OK, but as these are my Photos, i will be looking at online or another means of storage as well.

Theks to everyone for your help on here

Apple has a problem with their software. Spoke to tier 2 and my external hard drives will be come read only.

Administrator of this computer. As this computer is best before my options are limited. Hit and miss so software based.

Hi JasonFear

I am having a strang problem with my hard drive. When i connect it to my macpro in the disk utility it shows only the free space and dosen't highlight any option(First aid, Repair, Partition etc.).This is a 1 terabyte seagate external hard drive but shows only 4.14 gb drive and which i can not access. I have checked it into system profiler and it gives me following details

USB 2.0 Cable:

Capacity: 4.14 GB (4,14,20,53,888 bytes)

Removable Media: Yes

Detachable Drive: Yes

BSD Name: disk18

Product ID: 0x5020

Vendor ID: 0x0bc2

Version: 1.48

Serial Number: 2HC015KJ

Speed: Up to 480 Mb/sec

Manufacturer: Seagate

Location ID: 0xfa400000

Current Available (mA): 500

Current Required (mA): 100

Partition Map Type: Unknown

S.M.A.R.T. status: Not Supported

Please help me.

I can't believe this discussion has been going on so long without a clear solution that works for everyone. I've just about given up on my HD, and I have been using Backblaze online automatic backup. Easy as pie, nothing to do, it just auto backs up a couple of times a day.

Simple. At any point at any time either of two external harddrives will become read only. One is a Seagate, one is WD. I am the administrator of this system.

Software based (Mountainlion June 5 updates). Talking to tier 2 and they cannot believe that tier1 suggested a harddrive failing in my IMac. This is the support you can expect going forward. Little to none.

Try adding a 8 gig usb key and a 4gig file won't fit. It's a software issue (failure) that Apple will not admit. There are other forums and ways for Apple to pay attention.

Hi everyone - I have never posted here before but I thought I should let you know that one of the methods I read on here just worked for me - my WD My Passport just stopped being recognised from one day to the next - not showing up in Finder, but showing up in Disk Utility. I run a macbook pro 13".

Eventually after many attempts at various things that didnt work - I did this:

running Disk Utility / Verify / Repair - then THE REPAIR FAILED and it told me I needed to reformat.

Instead, I restarted the mac WITHOUT UNPLUGGING the WD, and it worked. Next time I looked in finder it was there.

I hope this helps someone. Its a really annoying problem and had me worried for awhile, but this is how I solved it.

THANK YOU.

I can't speak for everyone's situation, but for me it was clearly the power issue. I was using an external enclosure for my 2.5" SATA drive that I just took out of my MBP to transfer my files back to the new hard drive I just installed. I was using the NexStar TX and it even uses 2 USB ports to try to draw enough power, but it still wouldn't mount. I picked up a USB-->SATA cable with an external power supply and it mounted immediately with no problems. It sounds like as has been mentioned that the MBPs don't supply enough power via USB for some of these drives to mount. Hope that helps someone else.

I'm having an odd problem regarding recognition. Even though the external-cased harddrive's led is turning on, the disk isn't recognized by either the Finder, About This Mac/ More Info nor the Disk Utility. Any ideas on what could be happenning and how can I start solving it? Thanks in advance

That's the same problem I was having. I could even hear the disk spinning, but the MBP wouldn't recognize it. As soon as I got a different cable with an external power source, it mounted right up. That might not be your problem, but that would be the first thing I'd check.

dxs309, how is the flash drive formatted?

Mark

Anyone found a solution to this problem yet?

I have a 2 TB Seagate Goflex Desk Adapter USB 3.0, which I partitioned for time machine back up (1tb) and extra storage (1 tb) where I moved all my ebooks, photos and family home videos from last 15 years along with school files. My 2008 macbook was working just fine in backing up time machine and recogning the partition just fine till now where the external hdd light is on but neither system profiler or disk utility recognize the hdd. I'm in desperate need to find a solution without having to erase all my files. Some one help please!!!!

Thanks a bunch in advance 🙂