Q: Yosemite ejects external drives

I have no idea why this changed the scenario from this same issue so many are having and which I had had for a very long time, but after I disconnected my modem from my router plus reconnected all the router cables and moved the modem and router a little further apart, the ejection issue for my external drive stopped. I realize this makes no sense, but the external drive issue of ejecting has stopped.

I've done absolutely noting to my iMac --- not changed a single setting nor updated any app nor moved any wire and not changed a single daily work habit --- yet I I have not experienced any issues with ejecting now for some 10 days or more.  It's gone form daily to intermittent to o a fe time s month. And I have TRIED ZERO fixes listed here. Weird.  It's been an entirely arbitrary and random issue.

Update: I cannot remember the last time my disks ejected. In addition I have never disabled spotlight.

With my OWC Thunderbolt dock I have connected a huge number of peripherals. See bottom of post.

I cannot remember the last time my disks ejected which suggests that the issue may not be software but hardware. The external OWC Thunderbolt dock has its own power supply and as a consequence does not falter when a load is played upon the iMac.

Which brings me to the next observation. When I bought my iMac 5K since I do not do any gaming, I figured the standard spec graphics card was sufficient.

But to be honest, I think the 5K display requires a turbocharged 1,000+ HP engine to drive it. Working on images on my old laptop is faster at generating full resolution images.

I also have a DELL 2408WFP monitor connected as a second display.

Specs below:

Model Name: iMac

Model Name:                        iMac

Processor Name:                  Intel Core i7

Processor Speed:                 4 GHz

Number of Processors:         1

Memory:                               24 GB

Graphics:                              AMD Radeon R9 M290X 2048 MB    

Connected the following:

Firewire 800

16TB G Speed Q

12TB G Speed Q

8TB OWC Guardina Maximus

Lacie 600gb Extreme

Lacie 500TB portable

USB 3.0

WD Essential 2TB Time machine

Mobius 5-Bay raid system as JBOD into which I drop disks as I need them

This has been issue for me since I unboxed my brand new MacBookPro last month. After getting no help in support forums, took my machine into the Genius bar and they found that there were problems with the power supply. New machine needs a new logic board. It is on order and should be installed early next week. Will confirm if this helps solve the issue of the ejecting USB and intermittent network disconnects.

I had the same problem with my Seagate Expansion Portable. First thought it was the cable because when I switched to a USB 2.0 cable everything seemed rock solid, but after I bought a new USB 3.0 cable the problem reappeared.

So one possible workaround is to stick with USB 2.0?

Mid 2015 15' rMBP, OS X 10.10.4

I have this same problem as well right after upgrading to Yosemite a few months ago. And last month Apple ruined my iTunes library on top of things. Tried everything, nothing helped. Has costed hours and hours and hours. Very very very disapointed.

This issue has been a very serious one for me, so I am continuing to provide feedback in case it's of any value to anyone else. I am not especially tech savvy on OS. But, I have not experienced another external drive ejection for several weeks since my previous post saying the same thing. And again, I want to stress that I have not made any changes to my system or hardware, including cables.

I would much rather have the problem correctly diagnosed and solved than have it simply mysteriously disappear as abruptly as it appeared. Weird.

On a side note, a few weeks ago I placed a call to AppleCare regarding corruption in my contacts list. As part of the trouble shooting they had me run some software to check for malware and fortunately none was found. Nonetheless, the senior specialist had me remove Adobe updater, and two other third party installers for streaming content (which I occasion would do from my external drive), as well as all their preferences and start up files. I can't imagine this would've affected things, but who knows.

Has anybody analyzed the processes in the activity monitor that are terminated when their drives are unmounting and unmounting?

If there are no applications running it is a good bet that one of the processes is cauning the issue.  The unmounting and mounting issue started recently with my external Lacie d2 thunderbolt 4TB.  I have tried everything mentioned above and also upgraded to 10.10.4 hoping the elimination of discoveryd process would help but it did not.  I have noticed one thing that I have not seen anybody report.  One time when I restarted the iMac (21.5 inch, late 2012, 2.7Ghz Intel Core i5, 8GB 1600 MHz DDR3) the drive unmounted and mounted while the startup initialization bar was still In progress. One other item is that I only use my external drive to store my iTunes, iPhoto, and iMovie libraries.  Maybe the issue is from a process from one of those applications?

if anybody can provide insight into which processes could be causing the issue it would be appreciated.

Thanks.

My problems with ejected external drives during sleep mode  started when I switched from a Wi-Fi to an Ethernet network connection on my iMac. The events increased every time other Mac's connected to my local network. I have deactivated the Wake on Lan option in the Energy Saver tab and I did not have any issues since ...

Maybe some of you can give it a try and report if it helps too ... I am keeping my fingers crossed ... this issue had completely corrupted my RAID 1 external drive  ...

Looks like I fixed my problem.

I analyzed the console log files and found this pattern:

IOThunderboltSwitch::listenerCallback - Thunderbolt HPD packet for route = 0x0 port = 1 unplug = 1

disk1s2: media is not present

hfs: err 6 reading VH blk (vol=Lacie)

hfs: unmount initiated on Lacie on device disk1s2

IOThunderboltSwitch::listenerCallback - Thunderbolt HPD packet for route = 0x0 port = 1 unplug = 0

hfs: mounted Lacie on device disk1s2

I assumed it had something to do with Thunderbolt.  So instead of connecting my external Lacie via Thunderbolt I connected it using USB 3.0 and I have not had any problems in the last 48 hours.  I have even backed up about 250GB without any problems. 

I still have not determined the root cause but at least I can use the drive.

This has done it for me too. I have a Belkin Thunderbolt hub. I always had my external USB disks attached to that without problems. Upgrading to Yosemite changed that. Now I have my disk attached to a standard USB hub and problems are gone.

I had already tried this - it works with the drive that did not have its own external power source but not with one that does...go figure???? Anyway we should not be looking for a work around but Apple should be solving this ... i explained the issue to couple of photographer friends who were thinking of buying an IMac - i pointed them to this thread, now they are sticking with a PC - impact on sales will be the only way Apple listens.

Indeed.

For me it is working also with drives that do have their own power source.

This seems to work for me as well. I have been fighting with trying to get some  rsync copies to run but the drives kept getting "LOST". Now, with Spotlight for the drives on the target system, it seems that they are not getting hammered as much and therefore are not dropping out of availability.

Thanks

So would a external powered USB 3.0 Hub prevent this from happening?