Multiple external hard drives failures

My iMac has been through 5 external hard drives. The hard drives will work fine for a little while, then I will either get "The disk you inserted was not readable by this computer." or my mac will not recognize the HD at all.

I have a late 2009 intel 24" iMac 2.66 GHz intel Core 2 Duo 8gb 1333 MHz DDR3.

Is this with mains powered external drives? An older model may have troubles suppling bus power.

3 of the HD's were older. The newer ones are 1tb western digital and 1 tb seagate. And yes, externals only. I thought maybe a virus, so I've ran several different virus scans. I also did a complete system restore twice.

Good luck on that virus scan business. Hint: that's not the problem.

The number one cause of this sort of error is not enough (or JUST BARELY enough) bus power to the external drive. If any of your externals have the option of external power from the mains, use that -- or the two-headed USB cable pictured below and see if that doesn't improve the reliability.

chas_m said:

Good luck on that virus scan business. Hint: that's not the problem.

The number one cause of this sort of error is not enough (or JUST BARELY enough) bus power to the external drive. If any of your externals have the option of external power from the mains, use that -- or the two-headed USB cable pictured below and see if that doesn't improve the reliability.

Click to expand...

All of the external drives are external powered. And I've also tried that cable. Thanks though.

How are you removing the drives? They should be unmounted before you pull the cord out. If you just pull out the cord, or turn off the drive, or interrupt the power, the drive can be left in an unreadable state. Also, are you using a hub or are the drives directly connected? Have you changed the cables? Anything that interrupts data/power to the drives can leave them unreadable.

I always right click and eject the drives. I do a lot of photo/audio/video editing and can't afford to lose data on them. Which is exactly what ended up happening. 5 different times.

Hub? Cables?

directly to the USB on the back of my iMac. All powered.

How are the drives formatted? If you are using some third party NTFS driver, which one? (Here we recommend Paragon NTFS.)

I don't remember. But, all of them did work for at least 1 month before they stopped working.

Plug it it. Open Disk Utility and select the drive in the left column. What does it report?

Disk Description : Seagate FA GoFlex Desk Media Total Capacity : 1 TB (1,000,204,885,504 Bytes)
Connection Bus : USB Write Status : Read/Write
Connection Type : External S.M.A.R.T. Status : Not Supported
USB Serial Number : 01234567 Partition Map Scheme : Unformatted

Partition Map Scheme : Unformatted

Click to expand...

According to that, it's not formatted, which means that if it WAS formatted, it's somehow lost the partition data on the drive. Do you have another computer to which the drive can be connected to see if it's readable there? At this point, the only thing you can do is to repartition the drive, but that will cause the loss of everything that was on it. A product like Data Rescue 3 may be able to recover it, but there are no guarantees.

One other point. I've seen problems with drives with power-saving features where the drive spins down when idle for a time. Not all of the drives do that "politely" by first letting the OS know of the power down. OSX saw that as a disconnect and complained about it. I got rid of my Seagates for that reason, replaced them with WesternDigitals and have had no problems since.

Both of the 1tb hd's have seagate on the case. On the actual Hard drive, one says seagate and the other Western Digital. The one that says seagate, doesn't turn on at all. The Western digital shows up as a Seagate goflex... But, I'll try partitioning it and hopefully I'll be to use it again. I assumed that I would not be able to recover the data on them. But, I do need external hard drives. Like I said before, this is the 5th external hard drive to be corrupted. I need to figure out what's causing the issue before I waste more money on another hard drive that's just going to crash on me.

partitioning worked on the Western Digital. I'm not too worried about recovering the data. But, I'll use is sparingly to see if the same issue occurs. unfortunately, the other 4 failed to partition. I'm thinking they're frozen because I also don't hear them spinning.

Not spinning is a sign of insufficient power, or a failed power controller inside the drive. Having four fail that way is highly unlikely, but possible. You haven't given your location, but if your mains power is erratic, you might be helped by putting a Uninterruptible Power Supply (battery backup) between the mains and the drives. Another way to see if they are spinning is to try to turn or rotate the case. You should feel the gyroscopic effect called precession as you do that. The drive will try to move 90 degrees to your movement. If it does, it's spinning. If not, that's another confirmation that it isn't.

One more thought: I had problems with one drive because the power supply provided by Seagate was barely adequate for the demand. It failed. I complained to Seagate and they sent another, which also failed. I got a third party power supply with twice the power rating and it worked fine after that. You might see if you have a compatible power supply with a higher power rating available to try on the dead drives. Keep the voltage out the same, but look for higher Amps rating.

Thanks for the help Jake. I was thinking of getting a powered case that I can stack them all in. Your thoughts?

If they are OK, that's a good use for them. You could get a RAID enclosure, set it up for a higher level of RAID so that if one drive fails, you don't lose any data and be relatively safe in using them.

You are not saying how you formatted the drives. One hopes to journalled HTF+, all the Windows options are dicey, FAT32 being the least hazardous.

S.M.A.R.T. is not going to work in external cases, the software can't get past the controller. Not that S.M.A.R.T. is all that useful. I actually had a drive fail on me whilst I was looking at the S.M.A.R.T. which gave it a clean bill of health.

You are not using the same cases/cables/powerboard? Which may be the real problem