Not recognizing external hard drive

Hi Mark,

Yes I got peed off and formatted it to mac journaled.. Lost a load of stuff too. Years of photos and work... Should have stuck with a PC!!!

I agree with PlotinusVeritas about backups. Nothing is more important than having multiple backups, and with the price of terabyte drives dropping so low, and inexpensive, automated, high quality backup software (I use SuperDuper) there really is no excuse to not have multiple backups. I don't go to the extent of using DVDs and keeping backups off-site, but realistically I should.

Unlike PlotinusVeritas I've never experiences a problem due to a bad SATA card, although I have recently purchased some steeply discounted cases from which the drives had been harvested and was surprised at the cheap feel of the interface cards. I do however keep a universal drive adapter and a known good case/adapter card (from OWC) for diagnostic purposes.

It's also important to have good disk utility software available. I've tried many packages over my 20 years as a Mac user. Some good, some bad, some indifferent. I currently have Disk Warrior, TechTool Pro and Drive Genius.

I've had excellent luck with Disk Warrior. Kind of a One-Trick-Pony, but very, very good at what it does. The only utility I update the minute an update is available, and the utility I recommend buying.

TechTool Pro has, I suspect, caused as many problems as it solved. It does have a few useful features, duplicated by other utility packages, but I like the idea of TechTool Protection, which (among other things) periodically saves a copy of a drive's directory to another drive. I've yet to get this to work properly or test it, but Micromat is working on the problem.

Drive Genius is kind of an also-ran. It has a few useful features like surface scan, duplicated elsewhere, and a block copy feature, which I can see as potentially very useful, but I've never needed or tested it. It also has a utility called drive pulse which runs in the background and looks for file and directory damage. So far it has flagged one .plist file as having a problem, and that was from an obsolete version of software. (Given a chance TechTool Pro will flag dozens of .plist files, many from often used software, yet my system is very stable).

So I'll echo PlotinusVeritas' advice regarding backups and add finding a trusted utility package like Disk Warrior to the list.

The Saint01,

"Yes I got peed off and formatted it to mac journaled.. Lost a load of stuff too. Years of photos and work... Should have stuck with a PC!!!"

Um, I was going to suggest trying to recover the disk using utility software appropriate to the format of the drive. DiskWarrior if you had formatted it as a Mac drive or if you left it formatted as a PC disk, hooking it back up to your old PC and running a Windows disk recovery package. Just reformatting it as a Mac drive has pretty much eliminated any chance of file recovery unless you want to send it out to a data recovery service.

Mark Piaskiewicz1

I don't go to the extent of using DVDs and keeping backups off-site, but realistically I should.

Like Steve Wozniak, I also dont trust the "cloud", not referring to Apple, but to any "cloud", and certainly not for vital data Ive been working on for 20 years. There is no such thing as the "cloud" at any rate, its just anonymous server farms and 10s of 1000s of hard drives

A private www domain however is only $70 per year, and $12 per year to register, and you have total control over it. In light of that, It boggles my mind why anyone would trust anyone for "online backups", considering the cost is usually much higher than a private www site which can be bought and up and running in under 1 hour.

Yes, Saint still had other options before he formatted the HD, I cant stand to see someone lose important work, it just makes me cringe. 😟

As for DVD storage, ....generally Id consider it only for vital data you "cannot ever" dare think of losing. Even I cannot backup a 16 Terabyte PDF collection onto DVD, ...not economical; but for vital data, absolutely yes, and a necessary alaternative to magnetic storage.

These are the Taiyo Yuden JVC disks rated for 100+ year archival storage, for technical reasons the DVD +R are more reliable than the -R pictured, as is the case with any brand of DVD, archival or consumer-level, +R is more reliable.

PlotinusVeritas,

Any particular speed I should loook for? I've seen 8X and 16X.

Stay away from the 16X, they're a good bit pricier which is a minus, also the speed can cause a write error, which is the VERY LAST thing you want on vital data as a lifesaver.

The "forever DVD blanks" as some call them should be as reliable as possible, meaning:

only get DVD+R, only get 8X burn speed.

These are the disks:

JVC/Taiyo Yuden 8x Silver Lacquer 4.7GB DVD+R

Why DVD +R vs. -R ?

DVD-R has inferior error correction, inferior `wobble' tracking, and the fact its data writing methods look like an un-needed halfway point between CD-R and DVD+R. The wobble tracking I shall explain first, then the error corrections method, then the specifics of ATIP/pre-pit/ADIP optimum power settings.

This additional information on a CD-R is called the ATIP (Absolute Time In Pregroove), which contains how long the track is, where it begins, what the maximum and minimum writing speeds are, what formula dye it uses, who actually made it, optimum power control settings, and error correction data. The ATIP is stored as a frequency modulation in the wobble itself.

However, since the wobble changes subtly to encode data, it is impossible to use with the small size of tracks DVD requires, as electric noise in the laser pickup and wobbles introduced by the electric motor spinning the disc, these could easily be read as frequency changes in the real track itself.

On DVD-R, they tried to solve the problem with something called `pre-pits' where spikes in the amplitude of the wobble appear due to pits fully out of phase with the rest of the track (ie, between two spirals of the track, where there is no data). This can be viewed as a simple improvement over CD-R as it makes it easier to track the wobble (since the wobble is constant except for the easy to detect and remove spikes).

Unfortunately, this method as one flaw: due to electric noise in the laser pickup, it would be very easy to miss the pre-pit (or read one that wasn't actually there) if the disc were damaged or spun at fast speeds. The time to read a pre-pit is 1T (roughly .0000000038th of a second), which even for a computer can be easy to miss. DVD-R traded hard to track frequency changes for hard to read wobble-encoded data.

On a DVD+R, however, they came up with a much better method. Instead of changing the frequency of the wobble, or causing amplitude spikes in the wobble, they use complete phase changes. Where CD-R's and DVD-R's methods make you choose between either easy wobble tracking or easy ATIP reading, DVD+R's method makes it very easy to track the wobble, and also very easy to encode data into the wobble. DVD+R's method is called ADIP (ADdress In Pre-groove), which uses a phase change method.

I appreciate the detailed explanation regarding the differences between -R and +R. I've always been hazy on the different optical disk types and your explanation was very informative. Anyway, I've got a stack on order.

I haven't read through all these posts to see all the suggestions but when I bought a new 1TB WD My Passport and couldn't get it to show up for love or money here's what finally worked for me:

Go to Finder > Preferences> General> Show these items on the desktop. Make sure "External disks" is checked. Also go to Finder> Preferences> Sidebar> Show these items in the sidebar. Again, check "External disks".

Good luck to all.

Weeblerock wrote:

I have a 1 terabyte seagate external hard drive that I used to back up my PCs and tried to connect it to my Macbook Pro to transfer the files over from my old computers, but the Mac won't recognize the external hard drive at all. Any suggestions?

What specific type of Mac do you use? One with retina display or one without?

I have noticed that the macbook pro with retina display has only 128 gB while one without has around 500 gB.

I have the same problem as you, my mac isn't reconizing my Segate (mine is 3 TB) external hardrive. Except I don't have a PC and so I don't know if mine if it works on that, but I do recall that it was "seen" once on my mac.

What I'm thinking is that like the less memory for a retina display mac vs and non retina display mac, there is a problem between retina and non retina displays in this matter.

I really need the space on my computer, if anyone can verify my thoughts it would be good, I have way to much stuff I can't delete but can move to another storage device.

I apologize greatly for my bad grammar and misspelled words.

My LaCie rugged has just stopped being recognised at all by my MacBook pro retina. Seems to work with everyone elses computer. What gives apple?

Has anything changed? New hardware connected?

I also have a WD ext drive and it worked fine transfrring from the drive to the mac previously. My drive is intact, as it is automatically recognized when I tested it on another mac. But now, when I plug it back in to mine, no go. Also tried a Seagate and nothing is showing as well. Definitely a problem with the mac, not the drive. Please advise.

Just noticed your post and I've had the exact same problem with very similar Seagate products. I have 3 quality exts that are useless to me - and I'm no programmer, but I know my way around the OSX interface in terms of trying to reformat, recognize, relocate, and any other re- you can think of that makes us feel ********.

My only success that I havent seen mentioned is to make sure that the connecting usb cable is supplying enough power to the ext hard drive, especially if the computer is its only power source.

For some older and bigger ext models, there's even something called a power booster usb cable. Best bet is to check the product description and go from there!

You people need to check the MOST COMMON fault on external HD, its so common a problem, youd be shocked to learn the truth of it.

Your dead external hard drive is likely fine! Great hope for your 'faulty' external HD

7 out of 10 "dead" or unresponsive external USB HD are due to this. period.

Every year many 1000s of good perfect HD are thrown away due to this common weak link in external hard drives.

this is suck, does anyone experience in your imac didnt recognze your external hardrive?? mine it only give me turn on light, but it didnt show seagate in my monitor.....

i need big help for this......