Q: "Disk Not Ejected Properly" error after EL Capitan goes to sleep and wakes up again.

I have not upgraded to 10.11.5 and my problem persists, but I wanted to give a report on the Apple Bug Reporter... I reported this as a bug over a month ago. Their response was slow, but I was asked for a few different pieces of information over several weeks. In the end, they closed the report stating that it could not possibly be Apple's fault. They stated it has to be a drive issue and I should deal with Lacie. This is after reiterating that the drive works fine on a Macbook Pro running Snow Leopard with USB2.0 and on my iMac with ElCapitan via USB 3.0. The only trouble is when it's connected to the Thunderbolt port on the iMac. But Apple deduced that it has to be the Lacie drive... deal with them... case closed. I'm SOL.

Thanks Apple.

I did a clean install of 10.11.5 as I was having other issues so decided it was time!! I did not import any old preferences, only the apps from a TM backup. I'm still getting the same error every time I sleep the iMac with my LaCie 2Big TB drive. All other USB 3.0 disks are not affected so it's quite possible that there is a problem with LaCie drives. And LaCie desktop RAID manager doesn't work at all if using HW RAID configuration. And the HDD's in the LaCie are already showing as 45.7% health in DriveDX and not even one year old. Seagate 3tb Barracudas are the worst drives on the market. As soon as they fail I don't even want warranty replacements. Instead I'll switch the WD Red NAS or HGST Desktop NAS drives!!

Sadly, Kelly, my early 2009 Mac Pro's spontaneous drive ejections continue after the 10.11.5 update. 

I use a third-party USB 3.0 PCIe card, which I don't consider to be the problem since it works just fine with USB 3.0 drives in a SansDigital enclosure. 

As my affected drives are mounted in a Xbiaoi drive dock, I conclude the drive dock's USB 3.0 circuitry must be at fault.  But Keep Drive Spinning continues to be a solution that makes the dock (which i don't intend to permanently mount drives in) workable for my intended use.

A positive note:  a recently purchased late 2012 Mac Mini running 10.11.5 with a connected external SansDigital USB 3.0 enclosure has had no difficulty with sleep or ejection or mounting.

Hey guys, I'm really sorry to hear that you're still having problems. As for me, I have not had a single issue since I installed 10.11.5.

Here is what happened to me:

• Have the same problem, disk not ejecting properly after upgrading to El Capitán. Cannot use my transcend JetDrive, it keeps unmounting all the time.
• Tried updating to every Beta. No luck.
• Take my computer to the Apple Store, a specialist took a look and tried booting a clean 10.11.5 to check that the problem persists.
• The problem was solved in the clean 10.11.5.
• Installed the clean 10.11.5 image on my Mac and the problem stopped.
• After a few weeks without issues I installed Java 6 and MacPorts. The problem appeared again!

I am trying to figure out if the problem is related to any of these (Java 6 or MacPorts) I will install 10.11.5 from scratch again in a few days and then will try installing everything again until I find what is the problem.

Is any of you using any unusual software that could be related to this issue? It would help me to figure out what could be going on here.

Thanks for your help!

Danko

Add me to the list of those suffering from this issue, although it has gone from sporadic to EVERY time my computer sleeps for awhile since changing out my USB Hub.

I am running 10.11.5 on a mid-2015 MacBook Pro. I was using a Belkin 4-port Travel USB Hub. It was fairly inexpensive and non-powered. After upgrading to El Capitan, I did sporadically see this issue and while annoying, it wasn't constant, so I didn't worry too much about it.

Now, I have changed to an AmazonBasics 4-Port USB 3.0 Powered Hub and it happens EVERY. SINGLE. TIME my computer sleeps for an extended period (a few hours?). There are literally error messages down the entire right side of my screen when I wake it up.

That being said, my external hard drive (WD 1TB MyBook) is still connected and works with no issues. However, it does not seem to be backing up in the middle of the night anymore and starts backing up when I wake it up in the morning.

I read through this entire thread yesterday, hoping for a solution, and have tried a couple things (to no avail). I wanted to start small, because I'm no computer expert.

I started with switching my browser to Chrome, because I have had nothing but issues with Safari since upgrading anyway. It freezes on me all the time and I have been force quitting it for months. I thought it was worth a shot. I changed the default browser to Chrome, shut down all programs and restarted the machine. Left for the afternoon and when I came home, no joy! Error messages galore!

So I then tried unchecking the Enable Power Nap box. This morning, still no joy. And now I was just away from the computer for a short couple hours and the entire right side of the screen was still laden with error messages upon wake.

And finally, I will note that it looks like my computer does not seem to recognize the Amazon Hub as 3.0; it thinks it's a 2.0 Hub? I have no idea if it's not compatible, defective or what, but it sure looks like the 4 devices I have plugged into it are plugged into a 2.0 Hub (unless I'm just reading that wrong, because it does also say 3.0 Hub in there, but the menu under the 2.0 Hub is collapsible and contains the items that are actually plugged in):

Sorry I don't have anything to add to the conversation, but I wanted to chime in and say that I, too, am having this issue and it's extremely frustrating.

It is possible that the problem is related to your LaCie drive in your case, but I think this wide-spread problem is a System problem that Apple simply does not know how to fix. Unfortunately, I don't know how to fix it either. I've tried almost all the "fixes" posted in this and other Mac forums. The only thing that actually works for me is to prevent the Mac from going to sleep (System Preferences/Energy Saver/Computer Sleep).

Some observations that may or may not help:

I first encountered this problem with Mavericks on my 2013 MacBook Air, which has a single Toshiba 1TB portable hard drive connected to one of the MBair USB 2.0 ports. It went away after upgrading to Yosemite.

Meanwhile all was well with my 2011 iMac until I installed El Capitan in late 2015. It started happening sporadically, and none of the El Capitan updates so far (through 10.11.5) have fixed it. A "clean" reinstall of El Capitan also did not fix it.

When it occurs, I get notification banners for all four of my external hard drives. Three of them are Western Digital and one is a LaCie. One of the Western Digitals is plugged directly into a USB 2.0 port on the iMac and the other drives are all connected through a powered USB 2.0 hub. I also lose the EyeTV Hybrid analog/digital Cable TV tuner that is plugged into the powered hub. It reboots itself just as it does when the computer has been restarted. This suggests to me that maybe this is more of a general OS-X USB management problem than a specific issue with hard drives.

I had this issue on my 2011Imac 27", The concern only started when I update to El Capitan,, I run 3 external hard drives and Time machine, have tried every method I could think of

I found that the issue was fine with all my USB drives disconnected  then I reconnected 1 at a time and all was ok until I brought back in my USB Powered hub (TP Link) this only applied to one drive as there isn't enough sockets as std, I then read up on hubs and purchased a Hoo Too hub  (this reduced my Disk Not Ejected warnings by 90%) and is still this way 6 months later.

I recently had an issue with a corruption in my system and eventually had to reformat  CMD & R and then manually reinstalled my docs and photos etc as Time Machine was corrupted this left me with a fresh install of El capitan accurate to that day , I then started to think this may have fixed the disc error in full so left it in sleep overnight and woke up the next morning with the same warning and thats after a reinstall and a clean time machine , the only thing I can feed you guys is the Hootoo hub improved things although I dont think it will help everybody

Good luck

Alan

I did a clean install of OSX on my iMac and it did make a difference. I've since sold that and now have a brand new 5k iMac and it still happens but only very occasionally now, and still with my LaCie 2Big thunderbolt drive directly connected. My USB 3 RAID boxes are without any issues.

Exactly the same issue. What is wrong with Apple, this does not happen on my yosemite mac desktops. Every morning for the last month and a half, brand new el capitan mac desktop, "Disk didn't eject properly." WHY!!!

Upgraded to 10.11.6 and now I have all three of my external drives ejecting.

For 4 months, It was just my LaCie 2Big 6TB thunderbolt drive and only when waking from sleep.

Since upgrading to 10.11.6, my other two GTechnology GForce drives are both ejecting themselves. So far it only has happened during backups... I have one 6TB GForce drive (USB 3.0) set to backup my External LaCie 6TB drive via Time machine. So every hour, it tries to run Time machine and every time, in the middle of the backup, the GForce drive ejects spontaneously. Right in the middle of the backup.

Meanwhile... I have the other GForce (USB 3.0) Drive 4TB drive set to backup my iMac internal 2TB drive  via Carbon Copy Cloner. This task runs every morning, and every time, the GForce drive ejects itself in the middle of the backup.

For 4 months, these USB 3.0 drives have been running backups without issue. Since 10.11.6 a week ago, these things are ejecting at each backup.

So three drives, all different, are all ejecting now right i the middle of tasks. It can't be the drives. This is all since the 10.11.6 upgrade.

I'm about to carry all this stuff into the apple store and talk to a genius. SO EFFING FRUSTRATING.

Here's my story,

My Internal 2TB Seagate 7200 RPM drive failed after a got the same Improper Disk Not Ejected Properly Error message. Now my disk won't show up anywhere. Not in Disk Utility, Disk Warrior, TechToo Pro 11. It's supposedly dead.

Then a few hours later, I'm using the USB Flash Drive of Disk Warrior to check some things, and right in front of me the USB Disk ejects with the same "Disk Not Ejected Properly", and NOW that disk is useless and doesn't show up anywhere. Unbelievable!

Below is a screen shot of what I found in the console messages for my Internal Hard Drive?

My System:

OS X 10.11.6 El Capitan

MacPro (Early 2008) 2 x 2.8 GHz Quad-Core Xeon

Memory 32 GB RAM

Graphics Card AMD Radeon HD 7950 3072 MB

Any other thoughts?

Thanks in advance everyone!

And here is the error msg for the Disk Warrior Drive that supposedly unmounted all on it's own. So now I have both USB drives and Internal drives ejecting. wow this is something else.

El Capitan 10.11.6, same problem. Started after updating to El Crapitan. Mac Pro trash can with Thunderbolt Pegasus R6 RAID

2009 Mac Pro with third-party USB 3.0 card, using 10.11.6  --  Adding to the (strange) collection of issues:  I purchased a Unitek drive dock that connects via USB 3.0 and does not spontaneously unmount drives loaded in it.  My SansDigital USB 3.0 enclosures continue to work flawlessly.  My Xiaobi dual drive dock continues to unmount drives spontaneously.  The seller of the Xiaobi on Amazon read my review, contacted me, and believes I have a bad unit.  He is sending a new one.  I'm hoping that will fix things at my end.  It does seem to indicate that the issue may be with how well the SATA to USB 3.0 conversion is handled -- by the external enclosure and its synergy with Apple's hardware and software.