Yosemite ejects external drives

In the last three days I am getting these messages - all has been ok and suddenly started happening - Im on El Capitan 10.11.16, with a Lacie porsche hardrive, (time machine backup) ran disk utililty but keeps happening! and disappearing off the desk top when the computer sleeps!

This is not a problem that Disk Utility can fix. It's an OS problem with Sleep that is apparently never going to be fixed. It has persisted through several OS versions. It never occurs in Snow Leopard (OS 10.6). The one thing that has worked for me is to install an app called Mountain (appgineers.de). You can use Mountain's settings to automatically unmount attached external drives when the computer enters sleep and remount them when the system wakes from sleep.

HI - i do get fed up with 'things' mysteriously going wrong when there is no reason for it. This disk has never done this before and I haven't had this problem ever since Ive been using it. ( Ive had other problems with it but never this) Im assuming it may correct itself??? Ill take a look at "Mountain' tho so thanks.

Dear All,

I don't know if this is really a problem with Sleep, because I've had ejection problems when the computer first started up in the morning and was not in sleep mode. I haven't had much problem lately because I'm not keeping the WD drive that gave me the most problems plugged in. I'm working with two other WD drives, and I've found that if I keep only one active, it doesn't seem to have ejection problems. I have the same photos on several drives and I've come to the conclusion that while searching or working with an image that is on both external drives, the search function cannot keep up with both drives and ends up ejecting one of them. However, it can also be a very random ejection and happened to me yesterday when working with Adobe Bridge, which just crashed because it couldn't keep up with the required speed needed to do a file name change. The problem has improved considerably in the last month or so and I do have hope that it will correct itself in the future. My advice is to work with one drive plugged in at a time and try to move a little slower in your search!

OK - the first set of tests point to USB three as the culprit

Set up is as follows - MacBook Air (120GB SSD) 10.11.6 (El Cap), connected to WiFi for backups to a Airport Time Capsule and a mix of USB3 and USB2 drives/cases. Only 1 USB drive connected at once and all drives have a mains power block and no external hub.

First test:

TimeMachine connected over WiFi - running as ‘control’ disk backup

USB 3 box with Hitachi 1Gb drive - two partitions of equal size

Display off after 15 min

Prevent computer from sleeping automatically

Put hard disks to sleep when possible

Wake for WiFi network access

‘Power Nap’ off

Spotlight privacy not set on partition

No disk encryption

Backups over Wifi - all fine during and after this test

Backup for the USB drive:

• 2320 Base backup
• 5 overnight backups to USB drive all OK
• 1102 - fail message reported - cannot create folder / cannot ‘first aid’ / cannot eject / cannot add to Spotlight privacy - forced to reboot Mac to access the drive

Second test:

Drive with TimeMachine backup erased - Airport capsule left as was.

TimeMachine connected over WiFi - running as ‘control’ disk backup

USB 3 disk partitioned in two as before

Display off after 15 min

Prevent computer from sleeping automatically

Put hard disks to sleep when possible

Wake for WiFi network access

‘Power Nap’ off

Spotlight privacy set on partition

No disk encryption

14 TM backups

Locked up drive solid:

Despite not using the other partition I could not do anything with it either:

Third test:

I took the drive out of the box and put it in a USB2 drive case.

Again erased the partition that had the TM backup on it

I've not set privacy on this drive

So far it has been running 26 hours with no error!

I'll leave this for another day or so then move over the the MacMini as I can shuffle more data around on that than the Air can hold :-)

Unfortunately, my usb2 case does not recognise drives over 2 or 3 GB so I am limited to what tests I can run but in principal USB2 looks fine but USB3 has the issue - I can test a 4GB disk with Firewire and USB3 though :-)

Dear All,

Just though I'd report in. I activated my problem WD USB3 drive again this morning and after a bit the Disk Ejected notice came up for that drive indicating it had been ejected from the desktop, but it's still active and working, so the message is in error. I thought I'd give the problem drive a chance again and see what was happening. I have two external WD drives plugged in, the problem USB3 and an older USB/Firewire drive that is quite stable. I'll report in.

Thought I was doing well but I've just come in to:

This failed around midnight last night BUT I could still access the drives to see the folder structure.

Ejecting them worked first time - no force or anything.

I'll set it going again with privacy on both partitions.

Wonder if it is AV as well - I run SOPHOS on the machine so I'll take that off the external as well (machine is not used heavily and I have a SAN backup of any files I need).

So this run is:

USB 2

Spotlight privacy on the TM drive

SOPHOS AV to ignore the drive

Still with Time Capsule running (again zero errors reported)

All other settings unchanged

Stranger and stranger

Just picked up the Mac to check and found the normal list of 'none ejected' disks:

Looks like it has missed a whole day of backups on the USB drive AND the Airport device but all is working fine and I can access both drives and TM made a backup in seconds of me logging in. No idea why the Mac has gone to deep sleep this time...

The 'errors' on the screen seems to prove its tied into the USB drivers (not just USB 3) so I now need to set up a Firewire test - shame I do not have an adapter for the Macbook as I would have liked to use the same machine but I'll clear room in the study and sort the Mac mini out next week.

One interesting thing that helps to confirm this is a USB issue - I have an 64Gb SD card in the Mac all the time (holds my music on rather than eat SSD disk space) and at no time during these test has it ejected - Spotlight and AV are not set to ignore this 'drive' so should be accessing it now and them...

When you are troubleshooting external drives, there are additonal potential problems to deal with: the enclosures and/or the cables could be the culprits. The brand name external drives from the big names (WD, Seagate, etc.) are not easy to work with if you need to determine whether the enclosure is faulty. The enclosures themselves are not usually of high quality and they can be a major pain to pry open. I recently had to extract a Seagate drive from its unimpressive enclosure in order to pinpoint its failure to maintain a connection with a computer, and it was an annoying process requiring a pry tool. The drive itself turned out to be fine when housed in a better enclosure. The cable had already been ruled out as the source of the problem before I resorted to opening the enclosure.

I prefer to buy decent enclosures and choose whatever drive I want to install. Decent enclosures do not have to be expensive, and they are easy to take apart. Installing drives is typically very easy, as long as you have fingers and a screwdriver.

For a less than $30, you can also get a USB dock that can be used to access 3.5" and 2.5" drives. You can also get a dock that works with eSATA and Firewire as well as USB, but of course that costs more. These docks are very handy tools to have.

The enclosures I have are simple to swap the drives out - at most a few screws and the power / data cables.

One note I have is make sure the power supply is rated well above that retried by the drive - most cheap ones do not deliver what they say in any form of stable consistent output!

Some in this thread have suggested that the problem is related to USB. I have my MyBook Pro (RAID) external hard disk connected via a Thunderbolt cable. It ejects in the same way as reported by others in this thread at least once or twice a day. This interrupts backups, of course, and prevents subsequent backups.

I, too, can't believe this problem has existed since Yosemite, and it is almost two years and two MacOS releases later and it still isn't fixed. C'mon Apple. Show us you really care.

Let me add my name to the list of people with this problem.

For me the issue is for an external enclosure which holds 4 HDD connected with a USB3 cable to my system (10.11.6). Adding the drives to spotlight privacy didn't do a thing, well at least I don't get the warning anymore that the drives ejected improperly. The main issue is that the drives eject when the system enters sleep mode, then the enclosure thinks the system is off and fully shots down. When I wake the system the enclosure is off and I have to turn on the device again. Obviously this causes problems if the data is being transferred…

Consider my name added to the list of people requesting a permanent solution to this bug.

I found out in the last few days that the Sophus anti-virus program has been seriously impacting the Time Machine backups not matter how the drive is connected. This is despite having the destination drives marked for exclusion. Any one here have this disk drop issue / eject problem and NOT running an AV product?

Yes I have this issue since Yosemite basically every day, it got worse in El Capitan and I do not use AV products at all. However since moving to the release build of macOS Sierra two weeks ago this issue has not occurred once. The annoying part is Apple not being truthful about this and letting us know. Right now I "think" its fixed witih Sierra but I do not know for sure as Apple are being secretive as they have been from the very start of this issue.

Just upgraded to Sierra and soon after tried to switch my external OWC drive from Firewire (via Thunderbolt adapter) to USB3. When put to Sleep the problem reappeared. So, at least in my case, the issue continues from Yosemite.