USB Hard Drive Spontaneously Disconnects

I've been having the same issues with my MacPro - with both USB external drives, and FW 800 drives (seagate, WD portable and desktop externals).

I recently had it while my Drobo (redundant backup) was re-writing to a new drive - and this affected all my video data.

I get the same error message:

The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off. To eject a disk, select it in the Finder and choose File > Eject. The next time you connect the disk, Mac OS X will attempt to repair any damage to the information on the disk.

This happens when I've not touched anything - and I have sleep disabled.

Is this a MacPro power issue with the ports? I don't know if I ned to take my computer in - or buy specific drives. But it's happened repeatedly for several months.

I read originally that the Seagate USB drives had an auo shut-off - but that if you used the FW800 adaptors there was no issue.

I still get - on several diferent brands of drives - this odd error message when I'm not toucj=hing anything. It *also* happens when copying large folders (100gb) - which makes the data transfer stop.

Any help would be greatly appreciated.

Joe

• MacPro w/ 2.8GHz Quad-Core Intel Xeon "Nehalem" processor
• 16gb memory
• 1TB hard drive (x2)
• 18x double-layer SuperDrive
• ATI Radeon HD 5770 with 1GB GDDR5
• Running Snow Leopard 10.6.7 (for software reasons)

You guys get this when copying to Windows formatted volumes or just anytime at all?

Anytime for me - it's really random, but *seems* like it's generally happens after a certain legnth of time, if it happens.

I re-format all my drives for Mac OS Extended (Journaled) - since a lot of the the drives come as windows formatted (FAT32??). I thought it was just USB drive - but it's firewire (800) drives also.

Thank you for your help...

joe

Oh, wondered if it was the same as I get from time to time.

I have the same problem using FireWire 800. With a G-Tech D-Drive mini.

• Using the drive on my MacPro is working without any problems with USB and FireWire 800
• Using it with USB on my MacBook Pro is without any problems too.
• Same cable for both computers.
• Only with FireWire 800 on my MacBook Pro (Mid 2010) causing all this strange problems.

Someone recommended to use an AC adapter for the drive. I thought this could possible be the problem, that just this ports can not provide enough power for the drive. I will see.

My thread about the problem is here.

There are much older threads on this topic that likley contain solutions to your problem:

- https://discussions.apple.com/thread/2151621?answerId=17342929022#17342929022

- https://discussions.apple.com/thread/2151621?answerId=17529443022#17529443022

Also, I posted this a few months ago, its the general-purpose diagnostic procedure for electronic devices. If you follow it, you will either figure out the true root cause on your own, or you will be able to post enough information for people like me to figure it out for you.

For best results you have to do these steps, in order:

- Google your drive make and model, see if anybody else is having the same problem. If you are the only person on the planet with drive "XYZ" with a problem then chances are you have a hardware problem in the drive, computer, hub, or cables (not necessarily in that order).

- if there is a support site for the drive post a question there about your symptoms (and read/search previous posts). Again, if your the only person in the world with a problem...

- Search this thread for you drive make (not model) to see if there have been other problems with their products (actually this is a good idea for a google search too). I tell clients to do this BEFORE they buy something for the first time. This comes under "buyer beware".

- Do some experiments. Try the drive on other computers, different cables, no hub, different USB jacks. Try READiNG only small files, then large. Try WRITING small files, then large. Try it after it's been OFF overnight. Try it after the computer and hub have been OFF overnight. Try it with nothing else running on the computer. Change the drive format, does it matter if it's exFAT, NTFS, or OSX Journaled?

- Post your symptoms and test results here. If you want help and not just platitudes and "me too"s you must include the drive make, model and any other potentially useful info like date of manufacturer, the disk drive make/model iniside. Go into System Profiler and grab all the USB info.

- Check to see if the drive has the same USB chip ID as the two we have already found in problem drives. Googling the chip ID sometimes can tell you quite quickly if there is a problem and a fix.

I know this is potentially a lot of work, I go through this process nearly weekly for clients. The problems change, but the process remains is the same.

The only "quick fix" is to find a solution or workaround with Google. I will spend a few hours reading every post even remotely related to a problem, looking for clues to the problem or a fix. In most cases a workaround is acceptable - it depends on how annoying the workaround is.

Your describing a random drive RESET.

Something is making your drive shutdown, and then it RESETS and reconnects.

This is typcially caused by over-heating of the drive's USB interface board (which is not part of the drive itself, just the case). Or some other problem with it.

For this, I tell clients to buy a "drive dock" and then rip apart the external drive case to get at the drive and use it in the dock.

It could also mean the power supply for the drive is dying of old age too - anything that can cause the drive to "crash" and REST itself.

But when there is a repeatable time delay its usually thermal.

Now put it back the way it was and see if fails again to prove the pattern is true.

Also leave everything off for a few hours to cool down then power it up to see if it takes longer to eject.

On one of the other threads I posted links too we compared all of our USB hardware info and found its always the same USB chiip in the hub or drive that have a spontaneous eject issue. But that problem does not auto-reconnect right after.

Have you googled your drive make and model to see if its a know issue or product recall?

You should always Google the drive make/model. You never mentioned the drive make, model or size in your posts. If you add it I would Google it for you.

Some hubs - especially really cheap ones - have or can cause all sorts of data problems with drives.

An external drive puts a very heavy data load on everything between it and the computer. A low-cost hub will cut corners that don't effect low-data volume devices like mice, keyboards, mp3 players, even some web cams. But a hard drive or an HD camera streaming video is at or near the max data rate of the USB link. If anything is not 100% compatible with the USB specification it will "drop" a packet of data. Which your MAC will interpret as "disconnect".

For me, the solution has been to go to the Energy Saver control panel (system preferences) and uncheck "Put hard disks to sleep..."