Disk not ejected properly

There is working natively, and then there is workarounds... yours sir, is a workaround.

Yours sounds like a network issue (assuming it appears as a network volume), so the fix mentioned earlier may work for you (if you combine it with the big three - reset PRAM/nvRAM & SMC, apply the fix mentioned, leave the power off (everything) overnight - and then see if it still works.

PS. Do you get the identical "Drive could not be ejected" message?

Sorry I didn't research your earlier posts, I did read them but didn't connect you with them when I replied.

Please accept my apologies for the attitude, it was unintended.

PPS. You may wish to repair permissions on your boot volume (and even your NAS volumes) and see if that is what is causing it?! worth a try.

best of luck!

Just incase that doesn't work, after buying lots of usb3 enclosures and trying load of hard disks i found a solution that works on my 5k iMac...

1. Disable "put hard disks to sleep when possible" in energy saver

and

2. Using a usb3 hub inbetween the hard disk caddy and the mac. (I'm using a anker 3 port usb3 hub with gigabit port)

I found that ejects would start on a newley formatted disk when large file transfers ere happening, then then once the ejects started they would become more frequent until the external disk outlentmount any more. If i don't do one of the above options i get ejects either when i don't use the hub or when the mac wakes from sleep.

I have been following the voluminous thread of this topic. I have a late 2013 MacBook Pro, OSX 10.9.5. In my case the problem appears to lie with the USB 3.0 cable of the disk enclosure. Details are as follows:

I had replaced the MBP"s internal hard disk with a Samsung EVO 840 solid state drive, and intended to use the removed hard disk as a back-up. The Samsung came with a very simple USB3 cable with a SATA connector, about 3 ins. long. I bought a disk enclosure for this backup hard disk but on pluggin it into my computer the DNEP message would appear within a minute and then the hard disk icon completely disappeared without a trace even in Finder. I tried various procedures like rebooting, letting it be unplugged for a few hours etc. all to no avail. However, when I use the simple USB cable that came with the Samsung EVO sad, it worked perfectly. When the computer is put to sleep and then reawakened the hard disk is there on the screen and no DNEP message. I have done this now for a while, copying files from the SSD to the hard drive. I also did the Timed Back-up with this littlel USB cable with no problems whatsoever, but I have to be extremely careful as there is no disk enclosure.

I haven't had the luxury of being able to test a variety of enclosures, but I think the general issue is mostly with USB3, with some being affected by others protocols too.

I think I agree with you though, it does seem to be a software/firmware issue with some drives and controllers not working well with Mac OS X. My own setup is using a four bay drive box, which has FW800 and USB3 ports for each drive, FW800 connected to a Thunderbolt adapter has been 100% reliable here. I can also connect using USB2, and still no problems, other than slower speeds. USB3 immediately causes trouble, with drives disconnecting as soon as the Mac goes to sleep mode. However, is sometimes random too, with usually a couple of the drive disconnecting every time, while the others only disconnect sometimes.

However, IIRC FW always did have issues too, and it was always advised to get 'Oxford' chipsets in the controllers. USB as a whole has always been an issue on Macs, as they implemented the USB system different to other platforms, which often caused compatibility and performance issues.

USB3 does seem to be a right old mine field though, with even some complaining on Windows machines too.

TBH, my system works so well under FW800/Thunderbolt, that I see no point in throwing time, effort and money in trying to solve the problem with USB3. It'd be nice to pick up a bit of extra speed from the external drives, but it's not critical to my needs.

And, FWIW, to confirm it's more a USB3 issue, I have a couple of USB3 hubs, and both of those cause problems with sleep mode, even with no devices plugged in.

It is a real mess this.

Cheers

I have had issues, yes. while connected to USB3, my Lightroom images were very iffy (on a dedicated drive), losing the ability to save images, or edits, or create new folders. I could read the drive OK though. Reconnecting to FW800 via a Thunderbolt adapter was fine.

My Time Machine drive started cropping up with directory errors, and appeared to be a drive hardware failure. Again, reconnecting to FW800 works fine, and I had to reformat the drive and restart my Time Machine backup.

I've also had various errors appearing in the System logs when almost anything is connected using USB3, even an empty powered hub - causes random wake up calls and crashes. The same hubs connected using USB2 have no problems at all.

Although I haven't been able to try many different USB interfaces, the hard drive units are all different brands/models and show the same symptoms.

In the end I decided not to throw more money at the problem, and just stick with FW800, which has no problems whatsoever.

Cheers

Andy

This just goes to show how varied this problem is since it affects so many users in different ways. I wish FW800 would work for me, I was rather surprised when it had the same issue. Now that you mention it, my Time Machine BU did get corrupted once and I had to erase and reconfigure all over again. Plus, It actually has disconnected on USB2 a couple times, but so seldom, that using that port has been sort of a fix for the most part. On eSata and FW800, the enclosure consistantly disconnects every time the computer goes into deep sleep. Since the same exact enclosure (not sure about chipset to FW) doesn't have the problem, I may send the unit back while it's under warranty. I just want it to work reliably on one of the ports.

I have this problem most days when I first wake up the computer. I just tried Robin's suggestion from the beginning of the thread -- does anyone know if it is necessary to delete the System Configuration folder from Library? It no longer moves the folder when you drag it out of Library, it seems to copy it.

I also have an APC backup, but the master/controlled switch behavior is turned off so I don't think that would be the problem.

I use Time Machine Editor to only backup in the middle of the night, so that is probably contributing to my problem, but I don't want Time Machine making hourly backups. I would like to find a solution, worried about corrupting data...

This problem is years old. It's been bugging me on Apple laptops since the days of the G4 ibook. Different computers, connection types, external hard drives - back comes the problem. Apple stuff is reliable, and so are the problems! I might try changing the computer name as suggested, but it seems an obscure solution - why should that make any difference when it seems to me to be an inherent fault?

Sorry Apple, but I think it requires a proper fix.

Like a few other people have mentioned, my "Disk not eject properly" (DNEP) issue seems to have been tied to a small power trip. I have a lot of power running in my office including a couple computers, a TV, and a mini fridge. I finally noticed that I would see the DNEP message when the fridge would kick on. I unplugged the fridge last week and haven't seen the DNEP message since. Still it wasn't an issue back on Mountain Lion or earlier, but my setup hasn't always been the same. So think about how much power you're sharing on the same breaker with your External Disks.

"So think about how much power you're sharing on the same breaker with your External Disks."

@astoutj, that's about the most plausible explanation I've seen in the years I've been following this thread. The randomness of the DNEJ messages and failure of any configuration changes of any kind throughout multiple OS iterations from Mavericks through the beta El Capitan, along with Apple's seeming inability to fix it, suggests that power variations to the various hard drives may well be the answer. Some drives seem more likely to give the DNEP message, particularly USB drives with external power supplies. I've always had a problem with those, and none with my Thunderbolt external HD, which has no external power supply. Also, I get random "battery running low" or some such messages from my USB connected UPS, even though there's nothing of the sort going on.

I can't imagine what the fix is, then, since the computer or OS seems to be responding to an intermittent issue with the drives themselves, if you are correct about this, which I suspect you are.

I'm not getting any more HDs that require external power, and I may try to sell my WD MyBook on Ebay. Readers of this thread can look for it there and bid it up. :-)

I have two drives one has an external power the other is USB and the imac on my power..yet I still get this on both drives and sometimes individually so it is not a plausible explanation for all cases

I've now tried a number of different external drives. The only one that has consistently worked without ever giving me DNE errors is the LaCie Little Big Disk. Unfortunately, it is very expensive and has a limited capacity and application (very fast disk for video editing/photography), so it won't help many on this thread. Strangely enough, I tried other LaCie drives (D2 and 2Big) but they triggered the DNE error.

I can't believe this hasn't been addressed, since Apple has moved in a direction of limiting internal storage with the Mac Pro and other devices, essentially necessitating an external drive if you work with many or large files.

Perhaps we should start a list of external drives that don't cause problems?

OK, I withdraw my statement about plausibility.

We can start with a g-Technology G Drive Mobile, 1 GB, which runs on Thunderbolt or USB 3.0. I've only used it with Thunderbolt, so I don't know what happens with USB (maybe I should try that just to see), but in 6 months or so it has /never/ given me a DNEP error.

I got my first Mac this January. I have two external hard-drives, one for backups and one for my family tree info & photos. The backup one never ejects improperly, always stays connected but the second one, disconnects improperly consistently. I replace an older HD, which had been attached to my laptop, thinking that its age was the reason for the disconnects. Nope still disconnects. The old one never disconnected from laptop. So I don't think it is a model issue but an issue with Mac going to sleep. I saw somewhere that one person wrote some scripts that basicly pinged the hd every so often. But I really don't want to go this route.

I have read some but all of the comments here on the subject. Tried removing everything from Spotlight like one user suggestions. Nope still happening. With so many people with this issue all with Apple products I think it is indeed an Apple issue.

I only have an all-in-one printer attached, besides this hd and the backup. Oh & a desk light.

Apple please find a fix for this!!!! Does Apple monitor this site???

Very frustrating! Just about makes me want my old laptop back......Sigh.....

Greetings fellow DNEP sufferers!

New poster to this forum here. I have this issue on my 2013 Mac Mini with an external USB 3 Toshiba SATA drive (used for Time Machine), AND it happens on my 2013 MacBook Air with a PNY 128GB USB 3 flash drive and a Samsung 2.5" SSD in a USB 3 enclosure. Additionally, it has been known to happen while the computer is awake and being used. It also does it when coming out of sleep mode.

Here is where it DOESN'T happen: on my 2010 Mac Pro tower. That computer does not have USB 3 ports on the motherboard, but rather a third-party USB 3 PCIe card. The external USB 3 WD SATA drive (used for Time Machine) connected to the third-party USB 3 card has NEVER had a DNEP issue. Not even once in several months of use.

All of these machines are running the latest version of Yosemite as of this posting (10.10.4).

Here is a question I have: does this problem occur when a USB 2 device is connected to a native USB 3 port? I have an old external LaCie USB 2 SATA drive that I use for Time Machine on my MBA and have yet to see the DNEP. In my world, the evidence seems to indicate that it is a USB 3 thing because I have not seen it with my USB 2 devices.

I perused all of the posts here and don't recall seeing this particular scenario being addressed; however, with so many pages of posts to sift through ⚠, it is entirely possible that I overlooked it.

Thanks for any input out there!