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#35421 - 08/07/15 08:32 AM Unmountable external hard drive, read-only
deniro Offline


Registered: 09/09/09
I was thinking about using a second, backup hard drive when I found this old one in my stuff, a Seagate (I think) in an OWC FW400 enclosure. No off button. That always bothered me.

I erased the drive with Disk Utility. When I came back after an hour, there was an error message which I don't recall. My computer had gone to sleep in the meantime and I had to log in again, but it looked like the job was done. I had zeroed the drive and it was empty.

But now I couldn't mount it. Disk Utility after a while could read it and informed me through Info that the drive was now read-only, not writeable. All the options in Disk Utility are greyed out. I can't do anything to this drive unless I can mount it.

I will likely buy one. All I need is something cheap like a 200 MB Firewire drive. Hard to find, as it turns out, Firewire being a thing of the past. I will search ebay, but I still would like to solve this problem. I spent a lot of time on Google reading about unmountable drives but couldn't find an answer.
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OS X 10.11.6
iMac 21.5", Mid 2011
2.8 GHz Intel Core i7, 24 GB
AMD Radeon HD 6770M
Using Apple computers since 1980

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#35423 - 08/07/15 09:57 AM Re: Unmountable external hard drive, read-only [Re: deniro]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
if it had been sitting around for years it may have just plain died during the erase, from the strain of suddenly having to get back to work after months of idleness.

and 200 MB? good luck with that !
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#35426 - 08/07/15 01:13 PM Re: Unmountable external hard drive, read-only [Re: deniro]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
At the price of hard drives today, why stop at 200 GB? I just put together a bus powered OWC Express USB 3 enclosure with a "rebuilt" HGST 1TB 7200 RPM drive for $85. I could saved $15 by going with a USB 2 enclosure. Admittedly USB 2 isn't that fast, but for a backup drive how much speed do your need? A 250 GB 5,400 RPM drive would have only saved me $20. I have been using these enclosures for a while now and have been very satisfied. They are plastic, have no fan, and what appears to be minimal ventilation, but I have never detected any indication of excessive heat. I use one on my server and it has been absolutely reliable.

If you just have to have Firewire, the OWC Mercury On-The-Go offers FW800 (backward compatible with FW400 using the proper cable) for $73 bare and the same drive(s) will fit handily into that enclosure.

Sorry these are all bus powered so there is no power switch, but then none is really needed.

It takes longer to open the box and remove the antistatic packaging than it does to install a drive in either enclosure. The only tool needed is a size 0 Phillips screwdriver.
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#35430 - 08/07/15 03:22 PM Re: Unmountable external hard drive, read-only [Re: joemikeb]
artie505 Online


Registered: 08/04/09
The OWC Mercury On-The-Go has a switch and is bus powered from a FireWire port but requires a power supply to run from a USB port. (A "Y" USB cable that draws power from two ports may suffice.)
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#35431 - 08/07/15 03:27 PM Re: Unmountable external hard drive, read-only [Re: joemikeb]
deniro Offline


Registered: 09/09/09
My broken drive is in a OWC enclosure. I wonder if the enclosure is broken.

How fast do I need a backup? Very fast. Backups take too long. The faster, the better. But it's tough to find Firewire drives. I was hoping to spend as little as possible but it looks the best I can do is OWC 500GB Mercury ($127.75) because it's FW 400 backward compatible if you buy an adapter cable. Other than FW 400, my imac has USB 1, not 2 or 3. I don't consider USB an option.
_________________________
OS X 10.11.6
iMac 21.5", Mid 2011
2.8 GHz Intel Core i7, 24 GB
AMD Radeon HD 6770M
Using Apple computers since 1980

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#35432 - 08/07/15 03:31 PM Re: Unmountable external hard drive, read-only [Re: deniro]
deniro Offline


Registered: 09/09/09
For anyone interested, the broken drive is recognized by Disk Utility but doesn't mount. Disk Utility Info says:

Partition Map Scheme: unformatted
Writable: No
Ejectable: Yes
Media type: Generic
SMART status: Not supported
_________________________
OS X 10.11.6
iMac 21.5", Mid 2011
2.8 GHz Intel Core i7, 24 GB
AMD Radeon HD 6770M
Using Apple computers since 1980

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#35433 - 08/07/15 04:27 PM Re: Unmountable external hard drive, read-only [Re: deniro]
artie505 Online


Registered: 08/04/09
You may be best off buying just a new HDD, and if it doesn't work in your current enclosure you can buy a new one for about the same total cost as the OWC 500GB Mercury.
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The new Great Equalizer is the SEND button.

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#35435 - 08/08/15 04:48 AM Re: Unmountable external hard drive, read-only [Re: artie505]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: artie505
The OWC Mercury On-The-Go has a switch and is bus powered from a FireWire port but requires a power supply to run from a USB port. (A "Y" USB cable that draws power from two ports may suffice.)

The switch is not an off/on switch rather it switches between the external power supply and bus powered mode. Depending on the particular drive mechanism in the Mercury On-The-Go, a USB 1.1 port may not provide sufficient power to activate the drive (it definitely won't with older drives), but USB 2 should work with most drives, and USB 3 ports will work bus powered. At least that is how it works on the one I have.

The OWC Express enclosure with a modern drive will work bus powered with USB 1.1, 2, or 3.
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#35447 - 08/08/15 11:37 PM Re: Unmountable external hard drive, read-only [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Originally Posted By: joemikeb
Originally Posted By: artie505
The OWC Mercury On-The-Go has a switch and is bus powered from a FireWire port but requires a power supply to run from a USB port. (A "Y" USB cable that draws power from two ports may suffice.)

The switch is not an off/on switch rather it switches between the external power supply and bus powered mode.

In OWC's pic of the Mercury On-The-Go the switch is labeled "Power Switch", but not "On/Off", so I assume that you're speaking from experience. I assumed it was an on/off switch because the LED didn't light up until I flipped it, but that could also have indicated a switch from no power...no adaptor, to power...FireWire port.

The switch on my Mercury Elite Pro, on the other hand, is labeled On/Off.

OWC's pics of the drives don't contribute anything, because the Elite Pro lends itself to labeling directly on the enclosure while the On-The-Go doesn't.

Originally Posted By: joemikeb
Depending on the particular drive mechanism in the Mercury On-The-Go, a USB 1.1 port may not provide sufficient power to activate the drive (it definitely won't with older drives), but USB 2 should work with most drives, and USB 3 ports will work bus powered. At least that is how it works on the one I have.

The OWC Express enclosure with a modern drive will work bus powered with USB 1.1, 2, or 3.

My On-The-Go/500GB HGST HDD didn't power-up with USB 2 power (April 2010 15" MacBook Pro), nor does my Elite Pro/Same HDD. (No "Y" cable with which to experiment.)
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The new Great Equalizer is the SEND button.

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#35448 - 08/09/15 06:58 AM Re: Unmountable external hard drive, read-only [Re: artie505]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
The switch on my enclosure is labeled On/Off as well, but from experience using an external power supply it applies to the external power supply.

I did add the caveat of "depending on the particular drive mechinism. The original drive installed in my On-The-Go enclosure (removed from an early MacBook) would not spin up on the power from a USB 1.1 port (which was all I had at the time). The enclosure now has a new 1TB drive in it and will spin up powered by what Apple specifies as a USB 1.1 port, just as a similar HGST drive will in the OWC Express enclosure.
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#35457 - 08/09/15 11:51 PM Re: Unmountable external hard drive, read-only [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Originally Posted By: joemikeb
The switch on my enclosure is labeled On/Off as well, but from experience using an external power supply it applies to the external power supply.

I think that contradicts your "The switch is not an off/on switch rather it switches between the external power supply and bus powered mode."

I checked the On-The-Go and Mercury users' manuals, and both specify that the switch is for turning the unit on and off, and further

Originally Posted By: OWC
Even when the optional 5V power adapter is not connected, the on/off switch must be in the “on” position to use the Mercury Elite Pro mini. (Addendum: No equivalent language for the On-The-Go, but it worked the same way, as did my G-Drive mini.)

so, in at least in some cases, the switch really is an on/off switch. (If "The switch is not..." governs, it shouldn't be labeled on/off.)

(My years old G-Drive's instructions specified that the final step to be taken when connecting it - no caveats about adaptor or port power - was turning it on.)

I "rechecked" my Mercury to see if it would power up from my MBP's USB port and discovered that I had not checked in the first place (...an embarrassing oversight with a new purchase blush ); it indeed does, so I imagine that my On-The-Go also did. (It was my "ancient" G-Drive that wouldn't power up under USB port power.)


Edited by artie505 (08/10/15 01:19 AM)
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