External Drive keeps disconnecting

was running fine on my 1T Seagate until 10.8.3 update. Now it keeps disconnecting until Time Machine is dyfunctional.

Hello all,

I've had similiar issues with my external usb drives disconnecting also. Found out that the firmware on the drive had a bug that allowed the drive to sleep after a period of time although the OSX was set to not sleep.

Fix: Found the manufacture of my external drives had a firmware fix/upgrade that resolved this issue. Maybe you are having a similiar issue with firmware. Check it out and let me know.

Cheers,

Dale637

Hi Dale

You're probably right. I've had various external drives connected. Some work fine - others are problematic. I've tried hitachi, medion (WD), buffalo and western digital with success... no disconnects.

more useful discussion found in a separate thread

https://discussions.apple.com/thread/2151621?start=660&tstart=0

I have a mid-2011 Mac mini with an external hp drive and the drive kept disconnecting. I watched the syslogs and couldn't figure out why. I suspected it was my iPhone getting involved as well, possibly insufficient power, etc.

Anyway, some had suspected that it was the USB port so I picked up an external USB hub (externally powered) and the problem has seemed to disappeared. Still, the system stalls when the external drive is being powered up, but TM runs without any problems.

For those interested, the USB hub is the DLink one, 7 ports with 2 high current. The iPhone plugs into one of the latter and the drive plugs into one of the regular ones.

bjl

okay, not sure what happened, but after about a month of the above solution working for me, it started ejecting again. mind you I never turn off or hibernate my Mac, so perhaps something else is happening. I'll try a reboot at the next convenient time.

bjl

I have had this problem for years with a MacMini 1.8 Core Duo (mid-2007, I think). I first had the problem with a single WD firewire drive connected. I had a stronger 12V power supply lying around from another project, so I replaced the WD issued power supply. The problem went away and has not returned (2 years now). The machine has run both Leopard and Lion with this config.

Because this worked, I also replaced the power supplies on a Linksys router and a ZTE ADSL modem. Voila! I stopped having to reboot the router and modem every couple of weeks.

I still have two USB drives attached to the machine and both have their stock power supplies. The drives are not reliable because of the disconnect problem.

I'd wager that most people with the problem have a chintzy power supply on their external drive. A better power supply is expensive even from Asian suppliers on eBay. But, we can't stress enough the importance of stable power. It appears that MacOSX is sensitive to instability, but the success I've had with the Linksys and ZTE devices suggests that it isn't just the Mac.

jrt

definitely will try that!

bjl

I too had the same problems last weekend with my Seagate Backup Plus external drive to use with Time Machine. I kept getting popups to say I didn't properly eject the disk. After repeated trys, I contacted Seagate via their online email, they responded the next day and gave me a link to an updated driver. It worked, backed up fine and Time Machine continues now to backup regularly. So in my case, it was a driver update that provided a solution. Seagate's response was impressive and fast.

HELLO FRIENDS..

I SOLVE THE PROBLEM VERY EASYLI, JUST RELAX.. I USE EXTERNAL DISC TO EDIT MOVIES IN FINAL CUT IN MY MAC AIR AND MY IMAC ..

I UPDATE THE FIRMWARE OF MY EXTERNAL UNIT SEAGATE SLIM FOR MAC 500G AND NOW WORKS PERFECTLY..

I GOT CRAZY EVERY 5 MINUTES BECAUSE THE UNIT DISCONECT, I THOUGHT IT WAS A MAC ERROR BUT IT WAS SEAGATE ERROR.

HERE ITS THE LINK..

http://www.seagate.com/la/es/support/external-hard-drives/portable-hard-drives/s eagate-slim-mac/seagate-slim-mac-firmware-master-dl/

HAVE A GOOD TIME!!!! BYE BYE .. JOE FROM ARGENTINA.

Got the same issue with a WD USB 3.0 portable drive on my MB Air. Finally fix it when I updated the drive FW. 🙂

Latest WD Universal FW Updater 3.2.0.10D for Mac :

Fixes :

* Fixed compatibility issues with some USB 3.0 hosts where the drive would occasionnaly disconnect and reconnect to the hostn caused by the USB 3.0 link power management

....................... stop buying and using western digital hard drives. 😊

Consumer level WD drives are worst, and known for power drop outs due to poor quality SATA cards in external enclosures.

The new 4TB 3.5" WD drives are failing at an astonishing rate so high that it even shocks me (almost)

Hi,

I had a very similar issue with, after years of working perfectly, loosing connection with one of the WD hard drives constantly. (got the message that I didn't disconnected the hard drive in a proper way)

There was a non directly related cause.

As a result, I couldn't run both WD's at the same time and one failed no matter what.

After executing Command+S a few times, the iMac re-established the connection, but unfortunately only for maximum 40 minutes.

Until asking an Apple expert at the Apple Store who simply suggested to, as soon as I could re-establish a connection with the WD, go to Disk Utility, click the specific Hard Drive and click Repair.

I must admit that I thought the solution would have been a bit more complicated, especially as I have read quite a fair number of blogs and forums, handling this matter, and none of them mentioned this.

So far, all good, the iMac hasn't lost its connection for the last 10 hours and I copied a 100Gb folder from that HD to another location.

Well, it might help some of you as well.

Good luck

(iMac 2009, Mountain Lion, 2 external Hard drives Western Digital - non stop connected)

I've had this problem for months now and tried pretty much anything suggested here; I applied any firmware updates that WD provided and disabled suspend/sleep of both the drives and the Mac, to no avail. After at most a few days, the drive would disconnect when it got some load.

Today I looked at the power supply that WD provides with its drive; it's a very cheap looking Ktec supply that does 12V and only 1.5A and it's made in China. I have other similar supplies lying around for older drives (which had all been working great until they broke after several years of service) and those all look better built and provide more current (2 to 3A, usually).

I've replaced the Ktec supply with one that can provide 3A, and so far things look to have gone stable again. Not much to go on yet though, that was less than hours ago, but a 70GB Timemachine backup is still going without a hitch so far.

My theory here is that the lightweight Ktec supply is suffering from rather variable production quality, causing quite a few of them to not output enough current in a stable manner, causing those drive disconnects. That, or 1.5A just isn't always enough for these WD drives.

Just make sure that the outside of the connector is Ground ➖ and that the inside is ➕ and that it supplies 12V DC and more than 1.5A.

No dice, unfortunately. It disconnected again in the night following the day after I posted this. Time to swap it with a different brand disk and RMA this piece of junk.