Disk not ejected properly

When some external drives have no problems at all and others in the same operating environment have none, as seems to be the case here over three operating systems, about the only conclusion to be drawn is that there is some essential incompatibility with certain drive controllers and OSX. Whether that incompatibility can be identified and fixed is unclear, but until Apple investigates it at the engineering level, nothing is going to happen. My experience with Apple is that they make sure that anything made by Apple is compatible with other Apple products, but as for third party after market devices you're pretty much on your own.

I do agree about submitting a bug report as suggested above. If they see something, they'll tell you.

I'm not sure its only LaCie. Is there someone skilled out there who can (a) make a meta-anlysis of all the discussions on DNE and collect data on types (brands and models) of HD, version of OS, and symptoms (such as whether the HD reappears on its own never, some of the time, all the time) so that can be provided to Apple and us; and (b) collect information on HD drivers by types to correlate with above? Of course this is the kind of data collection and data analysis is the sort of thing we would expect from the manufacturers (Apple, LaCie, WD, etc.) but ......

See my response to Flarestar.

As to the attitude of Apple to third party accessories, there is a little irony here. When I got my new iMac the end of last year I looked for a robust, compatible external HD for Time Machine. Among the reasons I chose this LaCie is that it was one of the few external HDs in the Apple store and it had Thunderbolt at a time when only the iMac had Thunderbolt. Perhaps naively, I figured that Apple and LaCie had made some effort to coordinate mutual development of their respective systems, that Apple considered the LaCie capable of working reasonably well with the iMac, and LaCie was aware of what Apples need. While I didn't read this as a guarantee, it seemed like a modest mutual endorsement. Even though I did not buy the LaCie from Apple but another reputable dealer, the model was the same one.

Further, as I have pointed out to Apple, at the time, it did not make any external HD with anything close to the capacity. Now they offer a 3 TB Time Capsule, but not in Raid format. The Apple store has G-Force, LaCie and other drives. Maybe the store should be required to reveal compatibility issues.

If Apple is intending to drift toward a point where its own products are the only ones with cross-compatibility and users are "encouraged" to buy Apple external HDs, perhaps it is time that we "third party" sufferers were informed.

Finally, LaCie and other HD manufacturers who describe their products as compatible with Mac OS X or a particular version have some responsibility to tell us whether they are fully compatible, whether the HD manufacturers have taken timely steps to allow their drivers to work with newer OS Xs, and how these problems can be addressed most efficiently and without needlessly imposing additional expense on the end users.

Irony, yes, but it's more that there's no real communication between Apple and third party device manufacturers, and really none between Apple and the retail Apple Stores about which third party devices they carry. Different Apple Stores seem to carry different third party items of all sorts. But if Apple Computer doesn't know which devices are compatible, then they wouldn't be able to advise the Stores as to which ones to carry. And some of these devices work under some configurations and not in others. This is completely different from the Apple Store apps, which all have to pass muster with Apple for compatibility with their computers.

As for your suggestion that someone do a meta analysis of all the posts here, in principle that's a good idea, but in practice I suspect it would amount to nothing. Apple wouldn't look at it, and if they did, they wouldn't act on it. Surely all sorts of users with Applecare have called Apple Support over the years with this DNEP issue--we who use these forums are a minority among the total Apple user cohort--and Apple still hasn't come up with anything, even a "white paper" on it.

In my experience with Apple, if you submit a bug report with configuration logs, they will sometimes see something that explains the problem and tell you how to fix it. They did that for me with a USB network connection problem using a non-Apple phone. It was a duplicate kext file, and when I removed it, the problem was solved. So maybe if someone submits a bug report with one of these drives attached, Apple will see something. I sort of doubt it though. This really seems to be a basic incompatibility with some external drive controllers. If Apple would take the time to work with these external drives, maybe they could figure it out that way and get the manufacturers to make the necessary changes. Not to be repetitive, but that doesn't seem to be Apple's modus operandi.

I'm talking about Apple's online store through the Apple site.

As to the bug report, I'll look for the next opportunity.

Thanks

I must admit to having this problem with Seagate Desktop 2TB USB3.0 (on late-2013 iMac). I tried everything imaginable to fix the issue, firmware flashes, OS X upgrade, OS X downgrade, fresh network installs of both OS versions, but it continued (sometimes after 2 weeks of perfect performance). Being my time machine backup drive, these (UNREPORTED!!!) errors were unacceptable. The computer sometimes went for a week or more, without anyone noticing the little warning icon in the menubar.

I have a stupid (but strangely successful) workaround that is (relatively) cheap, and allows you to keep your expensive external hard drive as a Time Machine backup drive.

I purchased an mbeat USB2.0/USB3.0 powered hub (3xUSB2.0, 4xUSB3.0) and attached the Seagate Desktop to USB2.0 on hub. Been working flawlessly (albeit more slowly) ever since. I am yet to encounter a Time Machine overrun, even with 80GB hourly backup.

If you create less than 60GB of new data per hour, you may wish to try this workaround. The hub cost me AUS$35

Best of luck everyone. I hope Apple doesn't drop the ball (again) with USB drives in future OS X updates.

FWIW, I'm in the same boat as everyone here and have tried everything under the sun to no avail. I have an iMac 5k (2014). The *only* external drive I've found that doesn't give me the DNE errors is a LaCie Little Big Disk. It's an extremely fast Thunderbolt disk I use to store photos on, but it has a limited capacity: 1 TB.

Then I have a couple of Mercury Elite Pro enclosures from OWC that are USB3. However, I do not keep them powered on at all times because of this issue. I just connect them a few times a week for backup.

This is incredibly frustrating as it defies all attempts to determine the cause of the problem and even who is affected. It's obviously a large # of people, but not everyone. I've spoken to others with Macs and external drives that are not experiencing this problem. In some cases they are the same Mac models and the same external drive models that people on this thread have, so it must be some combination of both hardware and software, or perhaps some hardware glitch in certain (but not all) Macs.

For example, I've spoken to people that have the OWC ThunderBay IV enclosure with an iMac 5k and it works fine for them. But I tried that exact combo and it gave me DNE errors all over the place.

I am even considering upgrading to the newest model of the iMac 5k, though I don't really need to, to see if that solves the problem. El Capitan had no effect.

Just got off the phone with LaCie. Maybe there is some light at the end tunnel after all. Accordingly to LaCie its probably a case of bad firmware. They will replace my drive. Once its back i will let you guys know if it indeed fixed the problem. Well cleaned the drive.... lets wait and see.

I too have this problem. Preferences did not have that file and although I did all the other parts of the post, it didn't work. Looks like it is just one of many El Capitan problems.

Ok this is what has happened to my case :

I have a Mac Pro 2008 and just installed an OWC PCIe SSD few days ago. I tried to backup my iTunes library (2.4 TB) to an external 3TB hard drive (via PCIe's eSATA dock). I was expecting that it would be completed at least for 12 hours (the machine was in default of Energy Saver), however, in the morning I realzed my Mac Pro has been restarted and a sign that the disk has been improperly ejected.

I thought may be the cable was not plugged tight enough therefore I recloned the hard drive again, however, after few minutes, the clone action was stopped and a sign of Disk not ejected properly appeared again.

I have repeated the above, and same thing happened and eventually my hard drive got corrupted and needed to be replaced.

I am not sure whether it is hardware or software issue, therefore, I decided to replace the whole OS X from my previous backup. After the restore completed, everything seems ok (at least till now)

Therefore, I suspect that one of the system file may got corrupted, so restoring the OS X from previous one should solve the problem, meaning it is not an OS X nor a hardware problem in my case

My Mac Pro has three OS X on different bays i.e. 10.11, 10.10 and 10.10 (PCIe), it only happened with the 10.10 (PCIe)

Thank you, this worked for me on El Capitan.

Thought I'd share a bit of good news, at least for me...

Current setup:

- iMac (27-inch, Late 2013)

- Processor 3.4GHz Intel Core i5

- Memory 32 GB 1600 MHZ DDR3

- Graphics NVIDIA GeForce GTX 775M 2048 MB

- External drive: Vantec HX4R eSATA/USB 3.0 RAID enclosure containing 4 x Western Digital WD30EFRX RED NAS-rated 3TB disks

For over a year now I've been battling with the good old "Disk Not Ejected Properly" dialog on my external drive. For me it wasn't happening when the computer was sleeping but instead when I was actively using it. I could either saturate the external drive with write traffic (e.g.: copying lots of multi-gigabyte files) OR I could saturate the CPU with user tasks, but if I tried to do both at the same time I'd be guaranteed to get the DNEP dialog within a few minutes.

Having read through this thread a couple of times I'd tried various solutions offered:

- I'd been to Energy Saver preferences and unticked "Put hard disks to sleep when possible".

- I'd confirmed that the setting had taken effect in Terminal using: pmset -g | grep disksleep

- I'd been to Spotlight preferences > Privacy and excluded the HX4R from Spotlight indexing (as annoying as that was, being unable to search the drive).

- I'd even borrowed another HX4R enclosure and a set of Seagate disks to confirm that it wasn't my hardware.

I was convinced that it was a timing or race condition bug somewhere in the JHFS+ driver or the USB3 driver. Until last week.

Last I moved my entire computer setup to a sit stand desk and then I started getting the DNEP dialog when barely anything was happening to the drive. Even just logging in to the desktop. Disk Utility would also pop the dialog just a few seconds into Verify Disk or Repair Disk activities.

It turned out to be, for me at least, the USB 3.0 Type B cable connecting the iMac directly to the HX4R enclosure. It must have always had a fracture and then when it got moved last week became a full-blown break. And I must have used my cable when trying the other enclosure. Since getting a new cable I haven't had the DNEP dialog pop once. *Fingers crossed* *Knock on wood*

I'm sure this won't apply to everybody, but hopefully it will prompt someone to try different cables and maybe fix their problems. Good luck!

I finally have found a solution to my DNEP problem but it may not work (or be useful) for everybody.

I use the 'Mountain' application (see website http://appgineers.de/mountain/ ) to control external disks. In the latest version (1.6.2) there is an option to prevent disks from mounting upon connection (but you can still mount them manually).

With this option activated, I haven't seen any DNEP for the problematic external disk so far, also upon wake from sleep.

This solution is only practical if you do not use the external disk that often (luckily my TimeMachine disk does not give DNEP errors). Every time you need the problematic disk you would have to mount it manually, but with Mountain it's only one click away.

This also worked for me as I had migrated to a new MacBook. Huzzah!

Would you please let me know how can you fix the problem?

As the post to long,not easy to find out the solution.

Thanks a lot.