External WD HDD enters zombie state?

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Level 2

216 points

External WD HDD enters zombie state?

I have a new Mac Mini running Sonoma 14.6.1 with two new USB-C connected WD My Passport Ultra HDDs connected.

Occasionally after waking my Mac from sleep, the WD HDDs are in some kind of Zombie state where they still appear on the desktop and in the Finder, but nothing wakes the disks up or allows me to access their contents.

Clicking on the disk in the Finder sidebar shows "0 Files" however the available space remaining shown is correct.

The disks cannot be unmounted by dragging to the trash, or by using Disk Utility. Running First Aid produces the result shown in the screen shot.

The only way I have been able to get the disks to respond again is to restart my Mac. Then everything is fine and the disks have absolutely nothing wrong with them.

Any ideas on a less brute-force method to wake the disks up?

Mac mini, macOS 14.6

Posted on Sep 26, 2024 5:20 AM

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Answer 1

Allan Jones

Level 9

72,440 points

Sep 26, 2024 8:30 AM in response to Brendan Jones

WD bare drives are good. I use their 3.5-inch "Black" series for all our desktop Mac backups, but not in WD enclosures. WD enclosures, not so great.

Frankly, Passport models, based on a lot of reports here, have been less than reliable, especially as they age. They have to scab power from the computer. Many trouble reports are traceable to low-power issues. USB ports on computers can only supply a finite amount of power.

Some things to try with the drives you now have:

Try one Passport at a time. Do the problems go away? If so, it's likely the power issue.
Get a POWERED USB hub (comes with an independent power supply) and put it between the Passports and the computer. That way the drives get plenty of power. Remember, mech drives have electric motors that are more power-hungry than solid-state systems, and can get hungrier as the motors age.
If the drive will ever mount, use Disk Utility to see how they are formatted. If for Windows (most are) and you do NOT need to share the drives with a Windows computer, erase and reformat the drives to Mac. Some have reported this reduces the power issues.

I gave up on "name-brand" enclosures after years of struggle and now use only this enclosure for all our desktop backups:

https://eshop.macsales.com/item/OWC/ME3NH7T00/

It uses reliable, desktop-class 3.5-inch mech drives that take only minutes and one screw-driver to install, and have independent power. We have never had a failure-to-work in well over a decade of daily use with the current models. Our oldest OWC 3.5-inch external (now retired) is so old that it does not show up on my OWC purchase history that goes back to 2002! I pull it out a couple of times a year to test, and it still works.

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Answer 2

HWTech

Level 9

60,794 points

Sep 28, 2024 9:04 AM in response to Brendan Jones

Brendan Jones wrote:

You don't understand the power issues @Allan Jones is talking about. USB drives can be tricky & may not always work like people expect.

The Mac Mini USB-C/Thunderbolt port is capable of delivering 15 watts - more than enough to drive a WD My Passport Ultra drive when directly connected.

The drives work fine all the time except after the Mac Mini goes to sleep. If it was a power issue, they wouldn't work at all, or they would operate very flakily and unmount themselves.

There is still more to power than just whether there is enough power for the device. There is also how the external drive handles that power & communication. USB drives are not always that smart & can get confused or may just have issues with power management. Consider the possibility that when macOS goes to sleep that macOS may cut off power prematurely to the external devices before those external devices can actually get to their own sleep state leaving the external drive in an unknown state. When the laptop powers on again, the drive may power up from a completely powered off state instead of a sleep state. The way the drive communicates may be different, but macOS thinks the drive is just waking up to its previous state. The two systems are now in two totally different modes. When a drive is ejected from macOS.....macOS will not communicate with the drive until the drive is physically disconnected & reconnected. If you were to use a powered USB3 hub (or the a dedicated power supply if the external drive supports one), then that external power source can give the drive more time to finish moving to its sleep state. This is just one scenario I can imagine occurring.

I had an older Mac where I was forced to use a powered USB3 hub to connect external devices. If I didn't use the hub, then the external drives would cause the USB3 port on my Mac to "break" where the USB3 port was dead until I rebooted the computer. With the hub, I never encountered that problem ever again. This is real world example and not just some hypothetical case.

When you mix devices from different manufacturers you never know how they will interact with one another.

Besides, I don't have a lot of faith in WD products. Sometimes WD products can be very good, while other times they are pure junk with very odd & intermittent issues. WD has been that way for decades. For a more recent example, check out the major firmware issue with the SanDisk Extreme Pro SSDs (SanDisk is owned by WD) where the drives would disappear & would even result in data loss although WD never mentioned that in notes for the firmware update to fix the problem.

SanDisk Extreme Pro SSD Firmware Issues -- HWTech - Apple Community

In System Settings try unchecking Put Drives to sleep when possible

I did this and while it solves this particular problem, it creates a new one. The external drives now never go to sleep, which is not desirable for external HDDs if one wants them to last 🤷‍♂️

Actually macOS has an extremely aggressive nature where I have seen macOS kill internal hard drives through excessive sleep & wake cycles which causes the Load Cycle Count to exceed manufacturer's lifetime expectations. In my experience when this occurs, the drive performance greatly decreases & can have odd behaviors. The hard drives are otherwise completely healthy. With some brands of hard drives (especially Samsung 2.5" portable hard drives) tend to have a very low limit for the Load Cycle Count.

A 3.5" hard drive should be able to survive at least 50K power on hours which is about 5 years running 24/7 (they could go as high as 80K hours). The 2.5" laptop/portable hard drives tend to wear out much sooner than that mostly because they tend to be jostled around because they are "portable" which wears them down much more quickly.....even if the drive sits on a desk 24/7, the 2.5" portable drives may have a max life of 50K hours (probably nearer 20K-30K power on hours).

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Answer 3

HWTech

Level 9

60,794 points

Sep 28, 2024 9:05 AM in response to Brendan Jones

Continued....

Looks like there is no optimal solution to this, or it's not a commonly encountered or known issue,

Have you contacted Apple directly for official support for this problem? If not, then how is Apple even to know such an issue exists? Or WD? If you have not opened an official support case with either vendor, then why would you expect anyone else to do so? Because people rarely open official support cases, the manufacturers are unable to realize the extent of any problems.

You should be contacting WD for assistance since it is up to WD to make sure their product works correctly with macOS if they are advertising macOS compatibility. If they determine the problem is with macOS itself, then they are able to better leverage their position to get Apple's attention to look into the problem.

and I will have to muddle through with a bit more trial and error on my part.

So why not try the suggestions provided by @Allan Jones? I think the powered USB3 hub has the best chance of working..even allowing you to still sleep the drive. Just get a USB3 hub which supports the UASP protocol for best performance assuming your WD drive supports UASP.

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Answer 4

Brendan Jones Author

Level 2

216 points

Sep 28, 2024 4:16 PM in response to BDAqua

Yeah I went through a process of re-running the diskutil command from Terminal and seeing which process was “dissenting” the unmount and killing that, until PID 0 was the only process left “dissenting” the unmounting.

The three processes I had to kill were all related to Photos, including photoanalysisd.

Next thing I’ll try is to always quit Photos App before I walk away from the Mac long enough for it to go to sleep, since only the disk Photos was using went into this zombie state on this latest round of trial-and-error.

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Answer 5

HWTech

Level 9

60,794 points

Sep 27, 2024 5:17 PM in response to Brendan Jones

Brendan Jones wrote:

It is a brand new Mac Mini and brand new HDDs. So power or age is not the issue.

You don't understand the power issues @Allan Jones is talking about. USB drives can be tricky & may not always work like people expect. More than likely using a powered USB3 hub for the external drives will make a difference, or it will point us in the correct direction to look.

You need to try his suggestions and report back on what happens for each suggestion that fails.

It's clearly some kind of software bug,

Perhaps, then report the bug to Apple:

Product Feedback - Apple

where both the Mac and drives go to sleep, but on waking the Mac Mini, the drives kinda wake up, but not. The LED on the drives remains on when the drive is in this zombie state.

What you are seeing in macOS is just the saved state of macOS when you put the computer to sleep with macOS not refreshing the stale information. For some reason there is no communication between macOS & the external drives after waking the computer. It is hard to say exactly what this may be, hence the excellent suggestions from @Allan Jones to help determine where the problem may lie (plus the suggestions may actually be a "fix" to the immediate problem).

If the drives didn't wake at all or unmounted themselves, it would not be possible to click on them in the Finder sidebar and not get some kind of error message. Finder doesn't complain, but it says each drive has 0 files on them.

If I physically unplug a drive, I get the error message the disk was "not ejected properly", but when I plug it back in, it comes back to life.

As I mentioned in the above statement, macOS is relying on stale outdated information. macOS has not refreshed the information which is why there is such a disparity here. macOS has never been good about refreshing information in my experience....it is something I just accept as "normal" with macOS.

I really don't want to have to do that, or reboot my Mac, every time I wake it up.

Then please try the suggestions offered by @Allan Jones. If I had seen your post first, I would have offered the exact same suggestions.

Also @BDAqua's suggestion is a good one to try as well.

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Answer 6

Brendan Jones Author

Level 2

216 points

Sep 26, 2024 5:42 PM in response to Allan Jones

Each WD My Passport Ultra drive is directly connected to a USB-C port on the Mac Mini. Two USB-C ports to two WD My Passport HDDs. They are the only things connected to each port. It is a brand new Mac Mini and brand new HDDs. So power or age is not the issue.

I also formatted each one as MacOS Extended (which recommended for HDDs, while APFS is recommended for SSDs).

It's clearly some kind of software bug, where both the Mac and drives go to sleep, but on waking the Mac Mini, the drives kinda wake up, but not. The LED on the drives remains on when the drive is in this zombie state.

If the drives didn't wake at all or unmounted themselves, it would not be possible to click on them in the Finder sidebar and not get some kind of error message. Finder doesn't complain, but it says each drive has 0 files on them.

If I physically unplug a drive, I get the error message the disk was "not ejected properly", but when I plug it back in, it comes back to life.

I really don't want to have to do that, or reboot my Mac, every time I wake it up.

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Answer 7

Brendan Jones Author

Level 2

216 points

Sep 27, 2024 10:28 PM in response to HWTech

You don't understand the power issues @Allan Jones is talking about. USB drives can be tricky & may not always work like people expect.

The Mac Mini USB-C/Thunderbolt port is capable of delivering 15 watts - more than enough to drive a WD My Passport Ultra drive when directly connected.

The drives work fine all the time except after the Mac Mini goes to sleep. If it was a power issue, they wouldn't work at all, or they would operate very flakily and unmount themselves.

In System Settings try unchecking Put Drives to sleep when possible

I did this and while it solves this particular problem, it creates a new one. The external drives now never go to sleep, which is not desirable for external HDDs if one wants them to last 🤷‍♂️

Looks like there is no optimal solution to this, or it's not a commonly encountered or known issue, and I will have to muddle through with a bit more trial and error on my part.

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Answer 8

Brendan Jones Author

Level 2

216 points

Sep 28, 2024 6:38 AM in response to HWTech

OK it gets curiouser. Turning off "Put Drives to sleep when possible" didn't actually fix the problem. After the latest Mac Mini sleep, one of my external HDDs came back to life, but the other didn't. Running diskutil from Terminal had this odd result when I tried to verify one of the zombie volumes:

% sudo diskutil verifyVolume /dev/disk5s1
Started file system verification on disk5s1 (Photos)
Verifying file system
Volume could not be unmounted
Using live mode
Performing fsck_hfs -fn -l -x /dev/rdisk5s1
Executing fsck_hfs (version hfs-650.140.2)
File system check exit code is 8
Restoring the original state found as mounted
Error: -69845: File system verify or repair failed
Underlying error: 8
The operation might have failed in part because an unmount operation was dissented by PID 945 (/System/Library/PrivateFrameworks/PhotoLibraryServices.framework/Versions/A/Support/photolibraryd) whose PPID is 1 (/sbin/launchd)

So unmounting was "dissented by" one of Apple Photo's background processes. Even though Photos is not running (it was running - but on waking the computer up, Photos quit, saying the disk on which the photo library is located was on was no longer available). If I quit this and all other backround Photos processes it complains about when I re-run this command, I eventually get this error:

The operation might have failed in part because an unmount operation was dissented by PID 0 (kernel_task)

Why on earth would kernel_task dissent an unmounting?

I'm not brave enough to kill PID 0 (although I assume it would just restart?)

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Answer 9

g_wolfman

Level 4

2,152 points

Sep 28, 2024 12:07 PM in response to Brendan Jones

It's rarely the wattage per se that is the issue, as much as it is the available and required mA of current the bus can deliver. This is particularly true of 3.5" mechanical drives which need a fair bit more current than 2.5" drives since the actuator arm covers almost twice the surface area. Even with an elevator algorithm controlling the arm, the need to have comparable performance is going to mean more movement and more current draw.

Bus-powered 2.5" drives tend to flake out less than 3.5" ones because of this, whereas externally powered 3.5" drives have far fewer such problems. Of course, SSD are better than both statically speaking.

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Answer 10

Brendan Jones Author

Level 2

216 points

Sep 28, 2024 4:31 PM in response to HWTech

Have you contacted Apple directly for official support for this problem? If not, then how is Apple even to know such an issue exists?

No, because I cannot yet reliably state that “doing X, Y and Z in this sequence always causes this issue to occur” and eliminating all other causes. Lodging a “case” with Apple without sufficient information that enables them to reliably reproduce the fault won’t result in a resolution.

I was hoping this issue was perhaps a common or well-known issue that others had already done some diagnosis on and identified a fix for.

What I have found in my internet searches is that a number of people have encountered external HDD mounting/unmounting issues after upgrading to Sonoma that they never experienced on Ventura, e.g:

External drive support in macOS Sonoma is partially broken, and it's probably Apple's fault

Users complain Apple’s MacOS Sonoma screwed up their exFAT external drive access

So prima facie, this appears to be a Sonoma issue, and not a WD issue, although my external HDDs are not formatted as exFAT. But if Apple have changed their external HDD handling then it could have other weird symptoms like what I am seeing.

I haven’t tried the suggestion of a powered USB hub because they are not cheap and I don’t have the money to conduct costly experiments that might make no difference.

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