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

I have had this problem with my MacPro 3,1 and external SATA drives. Telling the computer never to go to sleep fixed the problem. Monitor can still go to sleep. I switched the drives to FW800 and the problem went away. I believe the problem is in the chipset that the vendors use in the external drives. So Apple probably cannot fix it. Since this problem does not occur on PCs good luck getting a chipset fix.

Except for one thing. I've been using Macs since 1984 (not kidding, I had the 1st Mac sold in Rochester, NY). And more recently, have been using the same external drives (I keep 3 sets going at all times, that is how important it is to my work) for several years. I never had any problem whatsoever until El Capitan. So I don't think it's a Mac vs. PC or a disk vendor problem. Apparently lots of other users have had the same problem - since El Capitan. Same drives, same routine, no problem until El Capitan. The scientific method identifies one variable.

I'm also in Rochester, NY.

I've had the problem since Mavericks. I have OWC externals. They could not come up with a solution.

I too have had the Issues and only from the day I up graded to El Capitan having read and reasearched all I could find and having spoken to Apple Support my conclusions were:

Disconnect all USB connections -This removed the error

Direct connect the external hard drives (I have 4)- No Error

Reconnect the Original error Drive 4 via my powered Used HUB (Targus Powered)- Fault reappeared

Re connect Direct - Error Removed

Checked the Power to the Hub -Ok but still an issue

Researched for an High Quality 7 Port Powered hub -Purchased a HooToo (highly recommended on Amazon)

Hub Arrived Today plugged in all works OK

Reset the Energy Saving to Default settings -All still OK

Carried out several Restarts and Sleeps all OK

I still think this is down to elcapitan, and think it is over sensitive to loaded /current drawing USB ports , I can see we all have all had a similar concern and it may not be right for all , it did cost me £30 but I would be happy to have paid that given the hours spent getting to this stage

I tried several variations of connections after this to make sure it is not just a fluke but to be honest it has been an instant fix, I hope this helps.

Alan

Alan - Good luck to you. Thanks for the details.

I've haven't used a hub, hard drives were always plugged in directly. Three different drives that I rotate. Two different manufacturers. All purchases within two years. Never had a problem until El Capitan. Resetting SMC worked for a while, had to do it again. All fingers point to El Capitan.

For me it's El Capitan too, because starting from my external 10.10.5 Backup does not show any problems... Unfortunately I changed too many files since the Update so I don't want to roll back to 10.10.

I found a utility app that works for me:

Downloaded the app "Mountain" and set it to "unmount drives before sleep" - this works. All external drives are unmounted automatically before the system goes to sleep and mounted after it wakes up again.

Additional information: The version of Mountain in the appstore is an older one that does not offer the above mentioned option. You need to update it to the latest one (for free) that is not sold in the appstore any more or purchase the new version directly from the companies website (which is in my opionion only fair as Apple does not deserve any share of the money for not implementing this function...)

Many thanks, JNewHome, I had the same problem with upgrading to El Capitan on my MacPro 3.1 using a Sonnet PCIe USB-3 board. Even with 10.11.3 the problem of not reconnecting USB devices after awakening is present (get the message "not ejected properly etc").

I went to the German developer website appgineers.de and downloaded the latest version of Mountain. You get 30 minutes (yes 30 minutes!) to test it before you have to purchase but testing it worked straight away.

Installing the Mountain App (£4.95) and ticking the "unmount volumes before sleep" means that when the system wants to go to sleep, Mountain wakes up and dismounts the USB drive (my Time Machine). When the Mac wakes again, El Capitan remounts the USB drive in the normal manner and everything is happy, without any intervention on my behalf.

That was £4.95 well spent!

me too! All works fine with the Mountain on board 🙂

Has anybody had any joy with 10.11.3? I tried Mountain, which worked for a while, but then the same problem came back.😢

Still no joy here. :-(

I went from 10.10.5 to 10.11.3 and once I did I immediately started getting the errors discussed here. My Passport Slim 1TB connected to an Amazon USB 3 hub, on a MBP Mid 2014. I haven't tried plugging in directly to the MBP because that would be very inconvenient and it used to work on 10.10 (all versions).

I tried Mountain, btw, and it couldn't unmount on sleep the two times I tried. I have no problem unmounting manually.

I'm going to try disabling power naps to see what that does. I have a suspicion that it's related to that, even though I don't remember seeing anyone here saying that was the cause.

I've had the same issue with 10.11.3.

Try UNCHECKING the "Prevent computer from sleeping automatically when the display is off" under ENERGY SAVER in the Sys prefs. It started for me when I CHECKED that box and has not happen again since I UNCHECKED it.

I also have the "Put hard disks to sleep when possible" UNCHECKED. "wake for Network access" CHECKED. "start up automatically after a power failure" UNCHECKED. "enable Power Nap" CHECKED.

I do appreciate all the work-arounds. However, changing a completely appropriate work flow (energy use, computer run time) just to prevent a potentially disastrous consequence is a SOFTWARE BUG. An unconscionable bug that I expect of fly-by-night ventures. I just can't believe how long this obvious bug has been reported without response. Does this mean all resources are on iOS? Are there any lights on in the Mac OS side? Yes, I'm frustrated.

100% agreed.

Preventing my Mac from going to sleep works, but this is a desaster in terms of energy waste and shutting down the system every time I leave it alone for some hours adds no credits for usability either. 10.11.3 did not help at all, I wonder if we ever get a perfect working system again.

Spending money in the (third party) App Mountain also only works fine if I do not access iTunes on my Mac via the Remote app or Apple TV. This always results in disconnected drives, that cannot be mounted without a reboot. If I was willing accept this kind of trouble, I'd get myself a system with a different OS.

Really frustrating and disappointing. 😟

Dear Cupertino please stop adding unnecessary features in a yearly major release and get back to providing functional systems.

That's what at least I changed for.