Anyone else having problems with external disks unmounting randomly/suddenly on Mavericks?

The thermal characteristics of a different drive may be different--ie., the hot-spots might be in different locations. So if you stick it on the same spot on the different brand it's possible the temperature reading won't be accurate. Maybe it won't matter, but just beware.

Good point but its a risk I would take to avoid WD drives. Actually while typing this I remembered that this problem really only became obvious when I put an external WD USB drive on the iMac so its possible that an internal WD is not such a problem. Maybe its only the combination of WD drives and USB.
Can anyone confirm or deny based on your experience?

As I mentioned, my problem is isolated to a 2TB WD black drive. I tried it in USB3 and USB2 enclosures every time to computer wakes from sleep, the drive fails to wake up or remount, but Finder believes the drive is mounted. So when I try to access files on the drive, it causes Finder to freeze up. Switching the drive off and on resolves the problem.

I also tried it in a Firewire 800 enclosure and it usually works, but I did get it to mis-behave once. That 2T WD drive behaves fine attached to my airport extreme.

I don't have this problem with either of my other WD drives (1T and 4T). BTW, that 2T drive had been working fine prior to Mavericks. So if you're having a problem with Lion AND it's with internally mounted SATA interconnect, I'd say you have a completely different issue than I'm having. I would not have any concerns about the WD block drive. I might recommend the 4T drive just because it's noticeably faster than the 2T on USB-3 (probably even more noticeable on a much-faster SATA connection.)

Just to be clear, my problem is that the drive doesn't wake up after the computer wakes from sleep. I *used* to have the problem where the drives would spontaneously unmount, but that was 10.9.1 or 10.9.2. I haven't encountered the un-mount problem for months.

Bart

To any and all - check the website of the manufacturer of the drives you have problems with.

WD has said their is a problem with running their software on Maverick so advised removing it if your are using it.

They will not know about problems with internal drives unless you tell them -- they also have their own user community discussing drive issues.

When I first put an external WD 1TB drive on my iMac I got lots of can't read and can't write errors when copying files. Then when I plugged in any other USB drive the WD drive would eject.

I don't know yet if the internal WD drive is causing problems or if it is only external WD drives plugged in via USB.

Thanks I will give it a try. I gave up trying to get help from Apple years ago but maybe WD will be more helpful.

My problem is:

I had 2 spare 3.5" 2TB internal drives, new, so I bought a dual dock/enclosure to put them in to connect it to my Mac Mini for an easy 4TB of storage.

I bought this one, as it claimed to be Mac compatible:

http://www.amazon.co.uk/dp/B00D1NR9MA/

All seemed well, both drives show on my OS X desktop as 2 separate drives. However after a few weeks, I noticed they had both disappeared from the desktop in OS X (i.e. ejected). There was no usual OS X warning about not ejecting the disc properly, so I assume they were ejected by the OS.

The unit was still powered up ok, so after unplugging/plugging back in, they showed up again, but the same thing happened after a week or so.

I tried a different USB3 cable, same problem.

I contacted Inateck, who said it must be faulty and kindly sent me a new unit. Exact same problem.

All other external USB drives connected to the Mac Mini NEVER randomly eject.

I should also add that my Mac Mini is set to never sleep, and I never manually sleep it.

Any idea what's going on?

I was almost sure the problem was WD drives connected via USB. My internal WD drive in my iMac became unusable and the free replacement was stolen by the Apple service centre so I replaced it myself with a 2TB WD drive.

It is fast and so far has zero problems. Then I realised that since I replaced the original internal WD drive I haven't had any problems and was able to upgrade from Lion to Mountain Lion. I have also had no further problems with the PowerBookPro running Mavericks.

The only thing they both have in common is they both used the same external 1TB WD drive in a big black case with a rounded front. This drive was a backup drive used on the iMac and used to copy files to the MacBookPro. It looks very much like this drive was causing the problem on both computers.

Just chiming in.... Never happened before but in the last week or 2 my 1 TB WD external HD keeps unmounting and remounting. Says that the disk wasn't unmounted properly. I then click ok, then it remounts (All 3 partitions, one being time machine). This goes on over and over again! I was able to do a disk utility on the external (before it unmounted) and everything said ok with all 3 partitions. This drive has been working problem free with time machine etc for a year. All my OS Mac updates have been done. Maybe one of them caused this??

Any ideas??

Fresh install of 10.9.4 here and am having the problem with a Samsung D3 4TB drive over a Kanex Thunderbolt to USB 3 KTU20 adapter. Only seems to happen during a large (400GB+) finder copy operation.

I was having worse problems with 10.8.4 during finder copies, but not with CCC or DU asr, or command line cp copies. Rendered the finder un-restartable without rebooting the computer. Re: Samsung D3 Station 4TB finder copy hangs

The problems were worse with a unpowered Orico hub, and I thought directly connecting fixed the problem... but no. It was better, but still not right

I thought 10.9 fixed the problem, but a few tests after I thought it was over, the problem is back. At least under 10.9 the finder just aborts the copy and otherwise keeps going. The USB3 port "dies", though. Unplugging and re-plugging the usb 3 connector causes the drive to spin up, but it won't mount. Removing the KTU20 from Thunderbolt and reattaching gets things working again.

The problem with diagnosing this is that it can take hours of testing to get a disconnect. So, right now, I think my Toshiba USB 3 drive doesn't do this, but without running the 400GB copy at least, say, 4 or 5 times, I can't be sure. I also think the problem only happens when copying files, but can't yet be sure.

Still, if it's just the Samsung, where does that leave me? Trying random brands of 4TB USB3.0 drives in the hopes that one of them deigns to work with Mavericks? I guess so. That would be better than not being able to use my Toshiba. I can still return the Samsung. Or, as far as I know, the problem doesn't happen with USB 2 ports. But, again, without many hours of copying, it's hard to tell.

Interesting post. I can only respond to improperly ejected disks upon sleep and disks not showing up in Finder or DU upon wake.

I have a 2014 MBA running 10.9.4 using 3 different USB 3 drives. Every time, upon sleep, wether its normal sleep or hibernate, the disks will improperly eject and often cannot be remounted without a restart, occasionally, 2 restarts. If I connect the drives to an older usb 2 MBA running 10.8.5, they all run fine using the same cable. Using a powered external usb port makes no difference, once sleep is effected, the drives disconnect.

Things I tried:

Now on third OWC (2 models) usb 3 drive and 5 different usb 3 cables - no difference.

Borrowed a Seagate usb 3 portable from a friend - no difference.

Disabled Hibernate - no difference.

Uncheck put drives to sleep - no difference.

Never sleep - works but not acceptable to me.

Using a usb coupler with a usb 3 cable and drive - no difference as well as unacceptable to me.

Install Jettison version 1.4.1d3 (beta) - works, earlier version did not, get it from the developer.

My experience and from reading the thread is this is an OSX issue with no eject command prior to sleep, usb port power being turned off upon sleep and, perhaps, no record of the drive having been there upon wake.

As a bandaid approach Jettison solved my problems. For the long-term, I've put 2 new Macs on hold until this issue is resolved as moving from usb 3 to Thunderbolt does not appear to solve the problem. This is a very common issue affecting purchasers of late model Mac's. If enough people would simply delay their Mac upgrades or return them the minute they run into the problem (the first time a usb 3 drive is connected) then perhaps Apple will start reacting. Or, try Jettison. Apparently a small 3rd party developer can fix OSX and Apple cannot or does not bother trying.

So, do you think Jettison would work for my problem... btw.. I'm using a firewire 400 cord with my 1TB Western Digital external hard drive.

SOLVED! I went to the WD website and installed the latest firmware for my drive and all ok 🙂

Is this the universal firmware updater? Did you install it from Windows, or is there a Mac version?

I have an older WD drive and there is a Mac version. Here's the link that I went to. Hope this helps.

Go here to find your drive: http://support.wdc.com/product/download.asp?lang=en

My drive was under older drives: http://support.wdc.com/product/download.asp?level1=1&lang=en

Then here (for me): http://support.wdc.com/product/download.asp?groupid=111&lang=en

If you aren't sure which drive if it's older... google the product number and you can see exactly which drive on amazon or somewhere. That's what I did.