iMac crashes when powering off external Thunderbolt drive

I have the same issue. Disk is ejected properly and I go to power it off and I get a re-boot and then the white screen.

There are other reports of an incompatibility between that drive and the 10.10.2 update. You have already found a workaround. Contact the drive manufacturer for more information (there may not be any.)

There is no mention of a beta in update 10.10.2 on my information in the Apple Store Updates section.

But there is indeed a serious problem with this update. Same here. Kernel panic after shutting down the LaCie drives. It is reported that the same problem exists with other makes.

Yes, this happened to me today also after updating to 10.10.2. In my case the external drive is the G-Technology GDrive with Thunderbolt 3 TB model and I am connected with thunderbolt. As stated in other posts above, I always eject the drive and then would power it down with the back panel switch. This always worked fine before but now, after updating to 10.10.2 it causes a crash. I also sent the crash report to Apple. Is there any fix for this, other than switching to USB?

I too am having this problem (LaCie 3TB, 2014 15" MacBook Pro. I found a solution, probably not widely applicable, but might help someone else ...

I happened to have a CalDigit Thunderbolt hub lying around. I inserted that in the chain between the drive and the laptop. Now I can power off the drive without crashing the laptop.

That might be a possibility, though when it works for you that does not necessarily mean it works for others too. Anyway, it is worth considering. Thanks.

A message from LaCie advises me (and everyone) to unplug all external devices when updating OS X. They say that it is possible that during the update relevant devices are searched and prepared for an update. So it may happen that something is being changed in the firmware of external devices even when the OS X update will not be installed on them. The existance of a copy or clone of the internal system on an external drive may be enough for the update to interfere even there. It seems that the very close bonding of internal HD and external drives is still unstable.

I can see where that would make sense. However, I had my LaCie drive disconnected during the update.

Exactly. It's not a guarantee that everything will work fine. This shows that the update is to blame.

Same issue:

- 4TB LaCie d2 Thunderbolt & USB3.0 drive (model # 9000303)

- iMac (27’’ mid-2011), Thunderbolt firmware version 25,1 and Port Micro firmware version 2.1.3 (as seen in System Information)

- OS X Yosemite 10.10.2

Unmounting LaCie d2 disk partitions is OK: the drive spins down and goes to sleep without problem. However when I take the power off (with the small switch at the rear of the unit), the iMac experiences a kernel panic.

This issue did not occur with Yosemite 10.10.1, and does not occur either with another LaCie drive (8TB LaCie 2big Thunderbolt drive, model # 9000246). So the issue is specific to OS X 10.10.2, and only certain models of drive(s).

We need a fix from Apple - the Operating System should be rock-solid in any circumstances.

Curiously, OS X does not write a kernel panic log with every occurrence. It’s only after the 3rd or 4th kernel panic that it would actually produce this log:

===============

Sat Jan 31 15:57:30 2015

*** Panic Report ***

panic(cpu 0 caller 0xffffff802241a46e): Kernel trap at 0xffffff80228e9774, type 14=page fault, registers:

CR0: 0x000000008001003b, CR2: 0x0000000000000000, CR3: 0x000000002565b000, CR4: 0x00000000000626e0

RAX: 0x0000000000070001, RBX: 0xffffff804e6e9000, RCX: 0xcb694f8798fc00ec, RDX: 0xffffff81e115d088

RSP: 0xffffff820d1f3e90, RBP: 0xffffff820d1f3e90, RSI: 0xffffff81e115d068, RDI: 0x0000000000000000

R8: 0x0000000000987939, R9: 0xffffff81e115d068, R10: 0x0000031b3cf5cc6a, R11: 0x0000031b3c5d5331

R12: 0xffffff820d1f3f50, R13: 0xffffff7fa4295044, R14: 0xffffff7fa42ab978, R15: 0xffffff8022ad66c0

RFL: 0x0000000000010202, RIP: 0xffffff80228e9774, CS: 0x0000000000000008, SS: 0x0000000000000010

Fault CR2: 0x0000000000000000, Error code: 0x0000000000000000, Fault CPU: 0x0

Backtrace (CPU 0), Frame : Return Address

0xffffff820d1f3b40 : 0xffffff802232fe41

0xffffff820d1f3bc0 : 0xffffff802241a46e

0xffffff820d1f3d80 : 0xffffff8022436683

0xffffff820d1f3da0 : 0xffffff80228e9774

0xffffff820d1f3e90 : 0xffffff7fa4295267

0xffffff820d1f3eb0 : 0xffffff7fa4298ad7

0xffffff820d1f3ee0 : 0xffffff7fa42951ed

0xffffff820d1f3f00 : 0xffffff80223624f9

0xffffff820d1f3fb0 : 0xffffff8022414dd7

Kernel Extensions in backtrace:

com.apple.driver.AppleAHCIPort(3.1)[93E1D2EC-50EE-3340-9676-0EA1E0B1AD45]@0xfff fff7fa4291000->0xffffff7fa42abfff

dependency: com.apple.iokit.IOAHCIFamily(2.7.5)[DAF0353B-16D5-385A-A0F3-FD5CF3BA07F2]@0xfff fff7fa365a000

dependency: com.apple.iokit.IOPCIFamily(2.9)[56AD16B5-4F29-3F74-93E7-D492B3966DE2]@0xffffff 7fa2b24000

BSD process name corresponding to current thread: kernel_task

Mac OS version:

14C109

Kernel version:

Darwin Kernel Version 14.1.0: Mon Dec 22 23:10:38 PST 2014; root:xnu-2782.10.72~2/RELEASE_X86_64

Kernel UUID: DCF5C2D5-16AE-37F5-B2BE-ED127048DFF5

Kernel slide: 0x0000000022000000

Kernel text base: 0xffffff8022200000

__HIB text base: 0xffffff8022100000

System model name: iMac12,2 (Mac-942B59F58194171B)

I have the same issue, however my Thunderbolt device is a OWC Mercury Elite Pro Dual, it only stated upon updating to 10.10.2

Yesterday Apple seem to have added 10.10.2 to the OS selection list in Apple Product Feedback, so it's finally open for posting. Not totally sure if it's really useful, but at least it doesn't hurt :-/ So let your voice be heard, and give Apple some LOUD feedback! https://www.apple.com/feedback/macosx.html

EDIT: there's a [lousy] work-around (sort of). If you're scared of filesystem corruption or nasty things that would occur due to repeated kernel panics, instead reboot to Recovery Mode (command-R) and eject / power down the drive from there. I'm not having kernel panics in Recovery Mode (different Thunderbolt driver maybe). Tedious, but hopefully safer.

Feedback sent to Apple.

My external drives are put to sleep, I no longer shut them down.