Disk not ejected properly

Add me to the list of people with the "Did Not Eject Properly" problem.

All Hardware is BRAND NEW out of the box 4 weeks ago:

iMac 27" Retina 5k (Late 2015)

El Capitan 10.11.4

External drives:

1. LaCie 2Big 6T Thunderbolt2 RAID 0

(External Power, Thunderbolt directly into the iMac)

2. GTechnology G-Drive 6T USB 3.0

3. GTechnology G-Drive 4T USB 3.0

(Both on external power, both connected to a USB 3.0 hub, connected to the iMac)

From day one, the LaCie 6T RAID has ejected itself ALMOST every time I wake the iMac up from sleep. Never when it was in use. But when I put the iMac to sleep, and wake it up the next morning, the LaCie 6T RAID is gone from the desktop and I get the error message. If I unplug the Thunderbolt cable from the back of the iMac and plug it back in, the LaCie shows up on the desktop and everything is fine.

The GTechnology G-Drives connected with USB 3.0 have never ejected themselves... Always work perfectly.

I tried getting rid of the thunderbolt cable from the LaCie and connecting it with the optional USB 3.0 cable and continued to receive the error message and ejections.

HHave you tried to reinstall your OS?

No, I have not tried that. It is a brand new iMac from Apple. This problem happened the first day I got it and plugged in my brand new LaCie RAID drive. I've read almost this entire thread and had not seen reinstalling the OS as a solution to this problem. Do you really think that might work?

I Am not too sure. But it worked in my case. I think I got some system corrupted

If reinstalled the OS does not help, then it could be hardware issue, and likely your Lacie.

I bought 4 Seagate hard drives recently, and two got corrupted and needed to be replaced.

I think a bad hard drive may cause this issue

I don't know whether this will be any help at all, but by fluke I found something today which may explain this message. I have never had it with my new macbook pro, (although I did get it regularly with my old macbook air) Anyway, I was having problems with pages taking ages to load, and someone suggested adding a Google DNS server to my server list - I think one was 8.8.8.8. and there was another one as well. It didn't sort out the problem I was having, but when I connected my hard drive to do my daily backup, sure enough, there was the message, which kept on popping up, so I couldn't back up. I removed the added DNS servers, and have had no problem since. Backup was fine.

Maybe it was coincidence, but I thought I'd put in my two halfpence worth - it just may help someone

Ok. It's been about a week now and I feel that a combination of a couple of the "fixes" recommended here have worked for me. Originally I tried the solution provided by @Robster50 (Robin) and it seemed to work for a few days, but the 'Disk not ejected properly' issue returned. In the end, doing all these things appears to have worked for me:

1. The original solution provided here by Robin
2. In Settings > Energy Saver unchecking 'Put hard disks to sleep when possible'
3. In Settings > Energy Saver checking 'Prevent computer from sleeping automatically when the display is off'
4. In Settings > Spotlight > Privacy added all the external drives to NOT be indexed by Spotlight

I'm not 100% sure if the last item is required or not and I may experiment with that and report back here. I did have one time in a week where my Time Machine drive did report the 'Disk not ejected properly' error but that is FAR better than before when I used to get these errors on multiple drives multiple times a day.

Apple still has no answers after 32 pages of complaints? Pitiful. I have two brand new Macs with El Capitan on my domain and have the same issue. Every morning, I come into the office and check both new Mac Desktops and see this error message, Disk not Ejected Properly. I only have one ext hdd plugged in on both Macs, strictly for Time Machine backups. If I cannot backup my Macs, then what is this new OS really for? We need answers and/or a fix. Both macs are updated with the latest Apple updates, yet still receiving the same error message every morning after waking up both computers. I disabled sleep mode and kept them on overnight. This did not resolve the issue at hand. I come in every morning and still see this same error message. I have 6 other Mac Pro desktops with Yosemite installed and no problems with the same ext hdds plugged in for only Time Machine backups. Please fix this Apple!!!

Its very sad to me that due to this issue happening every day on both my quite expensive macs that I have had to revert to booting up with bootcamp and using Win10 instead. At first to prove that this was not a hardware issue, which I have now proved its not, windows logs show no disconnection of usb devices, and overnight backups are always successful. My macs do not just do this when sleeping as none of them were set to sleep and it often happened while copying files to hard drives. Apple's non response on this issue has been really annoying and quite disgusting as its obviously an issue and being forced to go to Windows to make it work is quite pathetic.

One part of this I dont get, why "pull the system configuration folder to the desktop", this folder cannot be moved nor deleted as the system will not let you, so making a copy of it on the desktop seems pointless.

I can't see how this solution will accomplish anything other than confusing my Mac naming. I have had the "disk not eject properly" problem for several years, and have over that time spent tens if not hundreds of hours with Apple on the phone trying to fix it. I should note that only reluctantly would support allow my question to be passed along to technical. At that time, about a year ago, I was told that it was the fault of my external drive or external hub. I have an external HD (raid) running as TM which has (fingers crossed) worked now for several months without more than a handful of dneps. Likewise, my image archive HD, a WD MyPassport plugged into the iMac worked fine until several weeks ago. Then in the last few days it repeatly and sometimes rapidly dneped. When I hooked it into my external powered hub, it worked fine for almost a day. Then the same thing started happening. Apple has never addressed this problem wholesale; hasn't included any simple means of diagnosing the problem (if it is one with the drive or connections - my disk utility said the WD was fine). If the problem relates to some kind of machine address cache which gets dumped in the process of changing the machine name, then Apple should provide a more direct way of deleting that cache. While I appreciate you effort, I am not about to spend hours reconstructing files etc., if it doesn't work. Apple should address this issue directly. At one time I was told they would be; others have gotten a similar indication, but nothing has come of it.

Given the complaints about El Capitan so far, I am leery to update from Yosemite to it. If, however, it would accomplish the same effect as your workaround, I am almost more comfortable in doing that than the workaround that some Apple employee came up with. (PS - did she say if this would have to be done each time there is a dnep? Have you had any more dneps? What's your OS X?)

I get them all the time with El Capitan, pretty much every day when I come in to work. It is pretty bad that Apple has never addressed this problem. Thankfully it doesn't actually seem to cause any harm, at least so far...

I put a new connecting cable from the Mac to the ward drive. No problems whatsoever since, but it did it 100% of the time before.

As with alisonfromulverston I replaced the USB 3.0 cable on my external RAID and haven't had a single DNEP error since. You should try it.

This problem is widespread and persistent. I have had it on and off probably as far back as Mountain Lion. At one point I spent 20-30 hours on the telephone with Apple trying to sort it out. It happens to thousands -- judging by the many different discussion threads in Apple communities as well as other discussions, such as those of HD users, the number could be tens or hundreds of thousands -- of people using all sorts and iterations of Macs (iMacs and laptops) running on every recent OS for whom the OS(NB!) - not the user - improperly ejects external HDs of many different brands, with many different connections (both directly to the Mac and and through hubs).

Somehow my iMac has recently (before I upgraded to El Capitan) stopped dnep-ing the external HD I use for TM. (One of the curious excuses I got at one time was that I was using the HD as a RAID set and the OS, although it offers the option of setting up TM to a RAID set, somehow couldn't handle it.) The remaining problem with dneps is with another external HD I use exclusively as an image backup. After experimentation, I have come up with a limited fix, but one with virtually no risk. When the external HD is properly mounted, I manually eject it properly from finder and leave it unconnected for a while. When I reconnect, the iMac finds the HD and it seems to stay found for as much as several days.

I am extremely reluctant to try the alleged fix offered by Robster50. 1) I think those instructions incomplete: what happens to the file moved to the desktop? how does one avoid side effects like loss of connectivity on WiFi and to other cable-connected devices? 2) I am chary of changing the computer name (when I had problems with a new iMac, changing the computer name seemed to complicate the problem). 3) If this is a valid fix to many of the many thousands of problems out there: why hasn't Apple (a) sent out a general advisory or (b) incorporated the process into a major upgrade, as to El Capitan (or even done much the same thing invisibly).