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

SMC reset did nothing for me

2012 era macbook air

StorEDGE SD card

Update to this. It seemed that the SMC reset fixed it but what actually fixed it was that when I rebooted my machine from the reset I didn't start VMWare Fusion. I've now found that any time I have a Windows VM running I have the problem. If I suspend or shut down the VM before the Mac sleeps the problem goes away. So at least in my case it's a VMWare issue. I'm running VMWare Fusion 7.1.3 (3204469)

Add me to the list. One week old 5K Retina 27" iMac. The only difference for me was having to switch to USB instead of FireWire, connected directly to the iMac.

Tried the reset, but this morning I had a dozen notifications saying disk was not ejected properly. It must be connecting and disconnecting all night.

Same here. 27" iMac. External hard drives seem to be OK even after getting the "Disk Not Ejected" notification, but the SD card that contained the photos I was editing is completely erased. It basically formatted it after it fell asleep and will not mount until a restart. I should be able to recover using DiskDrill but still, this needs to be addressed.

Just to update things, I am still having the problem. I have tried all the things suggested above, except shutting down/suspending VMWare. I have Ubuntu installed on a VM and I am hoping that is the problem (although I always suspend my VM before shutting down...). I've run diagnostics from WD on the drive, and confirmed that my drive's firmware is updated and no problems have shown up. Here's hoping that a fix for this is discovered!

I finally got a complete work around. The interaction of VMWare Fusion and El Capitan causes issues with USB 3.0. I changed the advanced settings on my VMs to work as USB 2.0 and haven't had the issue since then.

HTH..Sam

I've got the same issue here on my mid-2010 MBP with a WD MyBook external drive. I'd had the issue in Mavericks & Yosemite, and it's actually gotten worse under El Capitan.

A quick Force Sleep used to reset the external drive connection; after waking up from overnight or whatever, I'd do a quick Force Sleep, and the external drive would come back online.

But now after waking up, my computer gives me the "Disk not ejected properly" message, and the Force Sleep trick no longer works, so there is no way to access the external disk at all: MyBook is powered up but my MBP won't recognize it. So I turn it off and back on. Then MyBook boots up and shows up briefly in Finder --- until El Capitan realizes that it was shut down improperly, and kills it again. It's maddening.

I have posted a couple times in this thread and I finally just gave up and tried a new external hard drive. Similar to the previous poster, I also had a WD MyBook External Drive (4TB Metal Enclosure) and I think it has failed on me. It took many attempts to copy the data from one HDD to another, with the drive completely disconnecting in the middle of copying data regularly. My new drive is a Seagate Backup+ 5TB and I have had no errors so far. I will continue to update this thread if any drive drops occur.

It looks as if 10.11.2 has fixed this issue...

No joy after update. 😟
I still get a dozen notifications after I wake from sleep.

At least the drive is mounted when I get in.

Since this is my Time Machine backup, I'd REALLY rather not wipe the HD, and start from scratch.

OK - looks like I spoke too soon. Shorter periods of sleep during the day seem to be OK, but when the machine wakes from overnight sleep the 'disk not ejected properly' notification is there and the external drive needs to be power-cycled to get it back up.

As an update to my last post, my 1TB Seagate Expansion drive is no longer disconnecting during sleep. This includes overnight and an 8-hour period when I had come out of my user account and left the machine at the login screen. In each case I had left the machine to enter sleep on its own.

I'll update with any more dropouts. Fingers crossed...

And of course it's just dropped out. Here's what Console says:

Dec 14 18:03:40 David-Cowlings-iMac kernel[0]: disk1s2: media is not present.

Dec 14 18:03:40 --- last message repeated 33 times ---

Dec 14 18:03:40 David-Cowlings-iMac kernel[0]: jnl: disk1s2: do_jnl_io: strategy err 0x6

Dec 14 18:03:40 David-Cowlings-iMac kernel[0]: jnl: disk1s2: write_journal_header: error writing the journal header!

Dec 14 18:03:40 David-Cowlings-iMac kernel[0]: disk1s2: media is not present.

Dec 14 18:03:40 --- last message repeated 48 times ---

Dec 14 18:03:40 David-Cowlings-iMac kernel[0]: hfs: unmount initiated on Time Machine on device disk1s2

Dec 14 18:03:40 David-Cowlings-iMac kernel[0]: jnl: disk1s2: close: journal is invalid. aborting outstanding transactions

Having the same problem here with my 3 TB porsche design Lacie drive. Having errors every time my MBPR (late2013) goes to sleep. Didn't have this before EL freaking Captain. The disk is connected through a usb 3.0. Just reseted the SMC and PRAM to see how it goes but as I can tell from the posts, i'll have no success.

Come on Apple, fix this!

It's ba-a-a-a-ck. I was not getting the disk eject error message for a few months after resetting SMC. But now it's back. Hard to believe we're up to 10.11.2 and this is still not fixed.