"Disk Not Ejected Properly" error after El Capitan

I had the recurring not properly ejected message on an iMac. The external hard drive was plugged into a USB hub. I disconnected from the hub and connected to the iMac USB port directly. That solved the message issue.

I have given my external drive its own power supply. Did not solve... Now I also see that it happens in daytime. Even several times during a long sleep period! So contact is lost and regained and lost again... And worse, it also happens on my OS X El Capitan 10.11.2 beta 2, which runs off that external hard disk: OS X crashes and restarts! So, sorry I think it will not be solved on the coming update...

My drive is connected directly, no hub. Funny: it happens very irregularly, sometime several times a day, then not at all for two days...

I too am experiencing this issue:Every morning since the upgrade to El Capitan I see the warning dialog 'not ejected properly'. It happens only during the night, not while my Late 2009 iMac sleeps during day time. I do have my iMac set to shutdown at 11:00 PM and Wake at 6:00 AM. Wishing I hadn't upgrade. Wish I had installed El Capitan as a bootable USB stick or HD so I could have tested it first and learned of all the issues.

Another one experiencing this issue. I have a powered (admittedly somewhat old) Iomega USB drive that I use for my Time Machine backups. I started getting the Disk Not Ejected Properly message when waking from sleep. This happens consistently now. Once it happens, the only way to get my drive to mount seems to be to restart.

I have tried:

- turning off "Put hard disks to sleep when possible" in Energy Saver

- connecting the drive directly to my iMac, rather than using a hub

No change.

I also got the message once when I was working, so it doesn't seem to be limited to Sleep issues anymore.

Never saw this message before upgrading to El Capitan.

Hi Alan

have you had any reply that helps to fix this, I get a screenful of "Disk not ejected properly" every time I come back to my Mac. My LaCie is mains powered on a USB3 and as others have commented the problem only started after upgrading to Al Capitan. Maybe Apple should spend some of their zillions we've all contributed to on fixing such basic problems within a more acceptable time frame.

I am getting a similar problem. I have 2 external hard drives, both Freedom. The small one is fine, but the larger one is consistently ejected with the error message, as soon as I plug it in to the USB port. It works fine on my old macbook air, which is running the original el capitan, but on my macbook pro (upgraded to 10.11.1, it just will not accept the larger hard drive. It shows, and ejects wit the error message, and then shows again a,]nd continues this cycle. It's really annoying that having bought a new bigger hard drive, I can't use it.

I would really love apple to sort this problem. Does anyone know when the new update is due? Let's hope it's solved then.So frustrated!

Okay, so I have had this problem for awhile now. I have a 2013 iMac, 2008 MacBook, and a 2014 MacBook Air and this problem only seems to happen with my 2014 MacBook Air. I tried finding a resolution awhile back and tried a few things that seemed to help people, i.e.:

"1. Pull out your ethernet cable and disable WiFi and any other network connectivity you have.

2. Open Finder, go to your computer and then select you Macintosh HD (or whatever you have renamed it).

3. Go to Macintosh HD - Library - Preferences

4. Scroll all the way to the bottom of the list and you will see a folder called SystemConfiguration

5. Pull this folder onto the desktop.

6. Go to System Preferences - Sharing and change the name of your computer, even just a little bit.

7. Reboot

8. Re-enable Wifi and Ethernet"

Nothing worked so I gave up for awhile and just tried to ignore it. The issue seemed to be getting worse and was ejecting the 4 drives connected to my USB hub every 5 freakin minutes! So today I decided to attempt to fix it again and after reading through countless comments on various threads I saw one person make a mention of clearing their VRAM.

FINALLY! CLEARING MY VRAM WORKED FOR ME!! And I haven't had an ejected disk since!

You can find instructions on how to clear your VRAM here: How to Reset NVRAM on your Mac - Apple Support

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R.
3. Turn on your Mac.
4. Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.
5. Hold these keys until the computer restarts and you hear the startup sound for a second time.
6. Release the keys.

NOTE: After resetting NVRAM, you may need to reconfigure settings for speaker volume, screen resolution, startup disk selection, and time zone information.

I hope this works for you guys as well!

Great suggestion. Unfortunately it didn't work for me. :-(

I'm going to be tempting fate here, but I tried your VRAM resetting trick on Saturday (5th Dec) morning, and as of 10:00pm on Wednesday 9th I've yet to have the drives disconnect.

No doubt my saying this will cause the drives to drop at a moment's notice.

I'll report back should my external drives start playing up again, but this looks like it's solved it for me.

Many, many thanks.

I'll have to let the fellow members of my local Mac group know how I'm getting on. Some of them are holding off upgrading to El Capitan because of this, and rightly so.

I have had this problem since I upgraded to Yosemite. I have two WD My Passport USB 3.0 drives, one for iTunes media and another for Time Machine backups. The iTunes media drive almost always ejects itself, despite the fact that I have changed the OS settings to not put the machine to sleep (in a pointless attempt to use it as an iTunes Home Sharing server) and also did so in the WD Utilities app. Still no luck. I am on the verge of resurrecting my late 2006 iMac to use as an iTunes server!

Thanks! I will give that a try. If it ever sees that there is an update, that is!

Aargh. Updated last night and things seemed to be improved. But just got back to my computer, woke it up from sleep, and saw that familiar "Disk not ejected properly" error. Sigh.