"Disk Not Ejected Properly" error after El Capitan

This happens to me too. I can't really provide specifics other than to echo the symptoms experienced here.

This is really a critical bug, as it can cause people to lose data. One of these 'incorrect ejects' corrupted my TimeMachine drive's partition info, and I lost the entire partition's data.

Imagine if it had been another partition with data I couldn't make a backup of.

Come on Apple, I used to think your software was mission-critical-land-a-person-on-the-moon reliable. Shouldn't that be a focus now that we have a lot of fancy features ??

I found your post because I had the exact same issue and now I'm reporting back with my solution.

As NeilHobbs pointed out, the root cause when you're unable to eject a USB drive after a TimeMachine backup is usually Spotlight indexing. When TimeMachine does its job, it will change lots of files. As a result, Spotlight will afterwards take a while to index the whole thing.

So I always couldn't eject my USB drive after a finished TimeMachine backup because Spotlight was still busy working on the drive. Since I don't use my USB drive for anything else than TimeMachine, I just disabled Spotlight indexing for my USB drive:

http://osxdaily.com/2012/01/24/stop-spotlight-from-indexing-time-machine-backup- volumes-external-drives/

And now I can eject it directly after the TimeMachine backup finishes 🙂

I started experiencing this issue on a new MacBook Pro (El Capitan 10.11.2, Seagate 2TB Desktop Media Drive).

I've found that I can prevent this issue from occurring by keeping a finder window open to a folder on the connected drive. Has anyone else tried this?

I'm not suggesting this as a permanent fix, but it's an easy prevention.

I tried this (setting my Time Machine drive as a Spotlight exception) and it made no difference. I have no problem manually ejecting the disk. I see the error when the computer wakes up from sleep, and then from that point onward I cannot get the disk to mount again unless I completely power down and then start up again.

I am another one. iMac 5k late 2014 with a LaCie 2big Thunderbolt 2 Drive used for TimeMachine and CCC Backups. After setting the Spotlight exception I am able to eject the drives. So far so good. But the drives eject after the the system go to sleep and I get the "not properly ejected" warning.

Bootet from my 10.10.5 backup everything is fine again. So it's definitely a 10.11 bug.

Tried Apple support without a successful solution

Also tried to change the energy settings not to switch off the drives - without success. Now I'm trying the option not to send the Mac to sleep mode at all.

Apple please do something about this quickly!!!!!

Try leaving a Finder window open to a folder on the USB drive. This seems to prevent my disk ejection during sleep and the "disk not ejected properly" error.

Tried this - left a finder window open to the USB drive. Still didn't make a difference. Same error message. (The only thing on the usb drive is my time machine backup.)

Hello. I add my computer to this discussion for Apple to have a larger as possible cohort. I hope for a fix ASAP.

I Have an iMac late 2009 and have two external hard drives : one is perfectly working (system : MS-DOS (FAT)) and the other one is recurrently ejected (system : OS X extended). On the non working hard-drive I cannot do anything as read files, copy file, etc. The disk is accessible and when I try to do something it is ejected with the message we all know well now. As I can compare between to disks, I think it has something to do with the system format of the disk. Unfortunately, I cannot change the format of the disk because I have data I cannot erase for the moment.

Thanks Apple for the solution you can give to this problem.

I don't think formatting is the issue. I have 2 USB drives, both formatted as Mac OS Extended (Journaled). One works fine (the one that is not used for Time Machine) but the other exhibits this issue.

I guess there are a couple different problems on this thread. I didn't have any problems ejecting my external drive, it would just randomly eject itself about every 3-5 minutes, then re-mount. For kicks and grins, I did turn off the Spotlight indexing and so far, knock on wood, they've stayed mounted. It's been a few days and they didn't even disconnect after waking from sleep (which is yet another problem referred to in this chain.)

Thought I'd share in case it helps someone.

After disabling Spotlight for the external drives I have no problems ejecting them manually any more.

But the random eject topic is still not clarified for me.

The only (interim) solution was disabling sleep mode. Tried everything else from SMC reset to NVRAM reset even leaving open a finder window - no success.

My Thunderbolt drives do not remount so after ejecting I have to restart.

If anybody finds a solution please share it

I disabled Spotlight on those drives, then I installed the App called Mountain, which unmounts/mounts drives before the computer sleeps/awakes.

The problem now only occurs if I have TimeMachine turned on (i.e. automatic backups).

So, as long as I manually back stuff up, I don't risk the corruption of data.

Not a full solution, but at least I'm not at risk of data loss.

A little disappointing, Apple.

I was able to fix this by connecting my Seagate external 2TB drive to an Anker 7-port powered USB hub instead of one of my iMacs USB ports. I still get a notification if a scheduled backup was attempted while the machine was in sleep mode, but the (numerous) 'Disk not ejected properly' notifications have stopped, at least for now!

Brand new MBP and LACIE Little Bigdisk hardwired directly to the Mac, and I have the same issue.Grrrrr!

Yet another person with the same problem. Zapping the PRAM did not help for me, neither did messing with the energy settings. I have not tried re-wiring my USB items so that the two external drives in question are directly connected because !A) that would take two ports, and B) It appears to have worked for exactly no one.

This problem occurred immediately upon upgrading to El Capitan. No other changes in hardware or software or configuration. Frustrating.