Can I force my USB drive to mount, or is it toast?

optical · Mar 30th, 2008, 11:49 PM

I have a USB external hard drive that I've been using for about a year. Recently when I try to plug it in, the device powers on (only powered by USB, no external outlet) and I can hear the drive revving up normally. However, it never appears as an entry in the finder. When I go to the Disk Utility program, I can see it makes an entry there, and the system correctly identifies it, and it's size and approximate freespace and file system, but it says 'Status - Unmounted'. I press the 'mount' button, and nothing happens.

I can run repairs and diagnostics on the drive but it never finds any errors and always comes back with a clean bill of health. In my experience a crashed hard drive won't respond at all - so I'm not totally sure if this drive is effectively toasted or if there is just some kind of goof in the OS that is causing it not to mount. I have other USB drive devices and I have no problem getting into those, it's just this one device that I can't access anymore.

Any help is appreciated!

eMacMan · Mar 31st, 2008, 01:25 AM

Have you tried creating a virgin account and checking to see if the external will mount when logged into that account?

Did you unmount the drive properly last time it was used?

Was the external disconnected when you ran the latest updates?

optical · Mar 31st, 2008, 03:07 AM

eMacMan:

I tried to create a blank account, and still no effect.

As far as the other two go, I can't be completely sure. I always make it a habit to eject things before unplugging them but occasionally even if something is ejected OSX will still complain and say that it wasn't... so again I can't be 100% on that one.

If this makes any difference, this is the exact wording on disk utility after running a 'repair disk' operation.

Code:

Verify and Repair disk “Untitled”
Checking HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Checking Catalog hierarchy.
Checking Extended Attributes file.
Checking volume bitmap.
Checking volume information.
The volume Untitled appears to be OK.

1 HFS volume checked
	No repairs were necessary

The only thing odd about this is that the drive *does* have a name and is not simply called 'Untitled'.

Rhonda · Mar 31st, 2008, 10:33 PM

I've been having a similar problem trying to get my Powerbook G4 to recognize my Lacie Rugged external hard drive. The first few times I plugged it in (USB) it worked fine. Next time it got flaky and would not show up in the Finder. It did show up in Disk Utility, so I chose Mount, and it worked. Next time I plugged it in, it didn't. Doesn't even show up in Disk Utility now. It works perfectly, however, when I plug it into a Windows machine. I can plug in my ipod and another external hard drive, as well as USB memory sticks and card readers with various type of cards, and they are all read without difficulty by the Powerbook, so it seems to be a problem between the Mac and Lacie.

From searching around on the web about this problem, it seems not uncommon. I've tried a few of the solutions offered, but nothing seems to work so far.

Does anyone know for sure which is at fault when the Mac won't recognize an external drive? Is it random hardware incompatibility? The Mac OS? Corrupted data on the drive (how come Windows reads it fine then???) And why would it work a few times then no more? I'm pretty sure I ejected it properly before unplugging it. (Which is another thing I wonder about - I regularly unplug drives and memory sticks and cards when I'm finished using them in Windows without ejecting them "properly", and never have a problem with corrupted data. What does the Mac OS do that could corrupt the drives?)

Is the ultimate solution reinstalling the OS? (Sounds like a typical Windows fix when nothing else will work!)

chas_m · Apr 1st, 2008, 03:21 PM

If you have disc warrior, see if that will repair your external disc. Otherwise, I think it's toast.*

*you might want to take the drive out of the case and put it in a different case just to be sure.

Quicksilver G4 · Apr 1st, 2008, 04:09 PM

	Quote:			Originally Posted by chas_m
	If you have disc warrior, see if that will repair your external disc. Otherwise, I think it's toast.* *you might want to take the drive out of the case and put it in a different case just to be sure.

It can't be toast if it works with windows though, maybe try formatting it?

rgray · Apr 1st, 2008, 05:35 PM

Have you tried the drive on annother machine?

krs · Apr 1st, 2008, 09:43 PM

First thing that comes to my mind with a USB powered drive is the power issue.

A powerde USB port is supposed to provide a minimum of 500ma at 5 volts; pretty much all USB drives I have seen require more than tat especially when they first spin up.
Are you using a Y-USB cable to pick up power from two USB ports?

Could be as the drive got older, it takes more current to power up and if one USB port was enough before, it may not be quite enough now.

optical · Apr 6th, 2008, 04:26 AM

I've done some more testing and now conluded that my computer will not mount *any* USB disk device, including 2 USB thumb drives and a cell phone with usb storage capability. The only exception? My ipod 5G.

Again, everything shows up in disk utility as unmounted, refuses to mount when I press the button, reports no errors, etc.

I have no problems with other USB devices such as mice, keyboards, etc. As far as power goes, the cell phone has it's own power source (it's battery) and that doesn't mount as well. My ipod has no problem charging from being plugged in, and both the ipod and the phone recognize that they are in fact plugged in.

eMacMan · Apr 6th, 2008, 10:52 AM

Which computer are we talking about?

Assuming this is the Power Mac

This is sounding like a USB issue but it might be a couple of other things. Try disconnecting any hubs, projectors, scanners, and ethernet cable. Everything but the KB and Mouse. Now shutdown the computer and physically unplug everything for at least 5 minutes. Plug it back in leaving the internet connection disconnected. Boot-up while holding down the "command-option-p-r" key combination. Keep it down until you hear the start-up chimes at least four times. Once you have booted with ethernet cable still unplugged check the date and time. It will most likely have reverted to 1956 or 1970. If it did not maintain current date and time you need a PRAM battery. Replacing it MAY resolve the isuue.

If that does not solve the issue, I would do a clean system install on the off chance that the OS itself is corrupt. When doing this, check the drive before installing latest updates. It is always possible that a particular OS or security update is causing the problem.