Yosemite ejects external drives

Consider my name too!

This is the first time I've posted to this thread but now it's December 2016! Should I be laughing or crying? Some folks say that a certain magic "click" fixes the problem, then return to say, "hmm, it came back." But maybe for some folks the problem really has been fixed. I would love to see a kind of accurate exit poll as a follow-up.

I'm still using Mavericks on my MBP with a powered 2.0 hub feeding a Seagate 2T used for TM. Like everyone, "Disk not..." pops up after sleep, but not always, and HD is not always unmounted. Have tried all the clever ways to make it work: by-pass the hub, make spotlight disregard the HD, disable all the sleep prefs, the HDDs are all different makes, and...oh maybe I haven't remembered all. The problem started a bit less than a year ago, yet did not happen after any upgrade to my OS, except maybe one of the security-java updates Apple puts out. It also occurs on my iMac which has 3 HDs on a 3.0hub. Both computers have a second monitor connected via Minidisplay Port. What did I leave out?

2017 is just around the bend. "Earth to Apple...! Is anyone home?"

GG

ccurrently I have found the upgrading to Seirra has helped with the Seagate drive but not a test WD drive (both USB3 and in the same enclosure). Interestingly, the WD is a green drive since pulled by them due to issues with the aggressive 'sleep' options in the firmware to keep energy consumption down...

So far after a week the Seagate has not dropped once inc a 500mb transfer.

Ah yes we have been at this for a long time. After moving to Sierra a month or so back I decided to see if the problem had gone away. By current work around is to use a Thunderbolt/Firewire adapter for a OWC 3TB HD. I switched back to a direct USB3 connection and after sleeping the "improperly ejected disks" reappeared. Bummer!

I really believe that this is mostly an OS problem, although there can certainly be hardware variables, such as faulty cables, etc. I have Mavericks, Yosemite, and Snow Leopard installed on my Mac Pro. I have also had test drives hooked up to it for El Cap and Sierra. The improper disk ejection problem never happens with Snow Leopard. So same hardware, but a different result depending on which OS I am using.

Had this problem too on my Macbook Pro 13" early 2011 running el cap when i had my Western Digital external drive connected to my cinema display. Last week I did a clean install of Sierra (but used migration assistent to transfer user account and settings) and the issue didn't occur anymore! So installing Sierra seems to have fixed it for me.

My external hard drives (xHD) with Western Digital, LaCie, and Seagate of different sizes (500 MB, 1 TB, 2 TB) with Macally Firewire/USB enclosures (Models PHR-5250CC and G-S350SUA) have been working without problems for years under the Snow Leopard 10.6.8 running on my Mac Pro (MacPro4,1) at home and in the office.

After a clean-install of El Capitan 10.11 6 on an internal hard drive (iHD) of each of the Mac Pro machines, the problems with the xHD started from day one. El Capitan either (a) does not see the xHD at all, or (b) after connecting the xHD, it disconnects the xHD randomly, or (c) sees the xHD, mounts it properly, completes its operations as required, and disconnects it when required (normal operation).

I have tried many of the suggested fixes, including disabling putting HDs to sleep, exchanging cables, providing additional power to the exclosures, resetting the System Management Controller (SMC).

Working with the computers has become extremely frustrating or untenable. I have been a customer of Apple sine day one.

How can Apple ignore this problem for so long?