6TB drives won't mount after restart in Mac Pro 2012

If you are familiar with that code, feel free to go crazy modifying and testing it.

I think most users will post a sticky-note on the computer that says: "Caution -- Server drives in Use! Don't just Restart: shut down, count to ten, start up."

FWIW: Using the utility "Cocktail", I set the startup delay to 30 seconds. Upon restarting, I was greeted by a gray screen for 30 seconds, then the login prompt appeared. Unfortunately, the two HGST 4TB NAS drives still did not appear on the desktop. I'm guessing the 30 second delay is not the right kind of delay to allow the drives to spin down and back up again.

Like I said my 2009 Mac Pro is dead so this is a moot point. I had the issue for a while and I'm interested to see if anyone figures out a solution.

I was using mine as a Plex server and the data drive wouldn't mount after a system update that restarted. The script I wrote would have solved that issue. At boot it would recognize that my drive was not mounted, schedule the machine to boot in 5 min and shutdown. For an office environment this isn't convenient.

I'm planning to swap my 6TB HGST drive into my Time Capsule and put a different 6TB Drive into my Mac Pro.

Can anyone confirm a current generation 6TB drive that does remount properly after restart? Preferably one that is compatible with the stock drive sleds?

I'm having the same problem with two [Model: HGST 2TB HUS724020ALE640 UltraStar 7K4000 HDD] drives I purchased from B&H Photo 29-day ago. I just sent them an email regarding my desire to return them.

B&H also carries Model: HGST 4TB HUS724040ALE640 UltraStar 7K4000 HDD. This model has nine 4-5 star reviews.

In December 2014 this 4TB drive was reviewed by a customer who stated: "Great drives! Added to a Mac Pro to build a server as a replacement for aging G4 servers."

The problem is obviously unique to Mac Pro 4,1 and 5,1 models. I have the 5,1 2010 model. I was able to load OS X 10.6.4 from the CD that shipped with the computer, and it restarted on the 2TB HGST drive. However, neither of the drives mounted on the desktop. My OWC Mercury firewire back-up drive did mount. The HGST drives would not mount, even after a full shut-down and re-start with the computer booted into the 10.6.4 partition. So I shut down again, and reinserted the original 1TB drive that shipped with the computer. When I started up with an OS X 10.8.5 partition on that drive, it appeared along with the OWC firewire drive, but the HGST drives did not mount. After a full shut-down and re-start they did mount, exhibiting the same problems discussed here.

As I could not find a way to post at the end of this discussion, I thought I'd reply to Grant Bennet-Alder, who helped me a great deal with my: "Eternal Beige G3-333 Quandaries" back in the day.

Sure would be nice if someone could develop a discussion aimed at determining the best "Enterprise Class" hard drives that are available for Mac Pro 2009-2012 [Model: 4,1 & 5,1] computers.

The 4TB drives are $95 more than the 2TB drives at B&H. 4TB would give me plenty of space, but HGST drives are clearly an iffy proposition with these Mac Pros. I might try the 4TB drives if B&H is prepared to swap out these drives and give me a full refund if they do not work. I need two drives -- and again -- it's a quandary!

Specs provided on the websites of both CDW and Best Buy indicate that the drive you have:

HGST hard drive Model: HUS726040ALE610; MFR Part# 0F23005, is designed to operate in a PC.

Shortly after I posted my previous message, I discovered that:

The hard drives I ordered, Model: HUS724020ALE640; MFR Part #0S03593, were not in the box.

The drives in the box were Model: HUS726020ALE614; MFR Part #0F23029, also design for PC.

I found an actual spec sheet for the drives I received and returned them, but HGST / Western Digital / AKA Hitachi has rendered the task of finding specs for their drives pretty difficult. Their claims that PC drives will format for Mac OS X are complete BS. Perhaps it's time for HGST to retain some QC personnel in Thailand to ensure that the part numbers on the box match the part numbers of the drives inside the box; and the prolific number of malfunctioning hard drives that people are discussing in this forum sound like the "stuff that makes the world go around" for attorneys.

I'm just "spit-balling," but based on what I read here and in various reviews it appears that:

HGST 4TB HUS724040ALE640 UltraStar 7K4000 HDD work well with the Mac Pro 5.1.

Clearly, the HGST UltraStar 7K6000 HDDs do not work well with the Mac Pro 5.1.

Check the MFR part numbers, against model numbers, and specs. If they're not right, return it.

Good luck.

Their claims that PC drives will format for Mac OS X are complete BS.

Disregarding for a moment that issues with spin-down&spin-up that make up this thread, If drive FORMAT were the only issue that statement is correct.

Kappy has observed that some Windows New Technology File System (NTFS) drives must be reformatted as MS-DOS first an intermediate step, then can be reformatted as Mac HFS+.

I've found a method so that I can use any problematics hard drives without the need for cold booting.

What I'm doing is preventing the problematic drive from mouting at boot. (I do this by editing the fstab file : with the terminal I add the hard drive UUID number to this file, you can check google for "how to prevent a volume from mounting at boot on osx" for more info).

I then use the free software "Semulov" to mount it from the menu bar but you can use disk utility if you prefer.

As strange as it may seem the hard drive now always appears in disk utility, even after restarting. it's just unmounted.

Without this trick I will lose my 4TB 7K6000 HGST Ultrastar hard drive each time I restart my mac pro (or switch between different OSX system partitions). Only a cold boot will bring it back to life.

In March of 2015 I encountered the above-discussed syndrome with an HGST He8 8TB drive model HUH728080ALE600 built in Dec. 2014 and after a great deal of trouble was able to determine that a combination of change(s) Apple made to the OS (and I see from the above investigations to the Mac Pro's also) and some feature(s) of the HGST F/W in some of their drives were the culprits. HGST Tech Support that month suggested that I could update the F/W of the drive myself but the remedy was completely impractical (long story), implying that they might have fixed the problem with newer firmware. To my dismay, today Oct. 2, 2017 I discovered that even one of these drives made in Oct. 2015, with F/W at least two versions newer than that first drive (and the other one from OWC that I tried in March, 2015) still doesn't mount on restart in a Mac Pro 4,1 with El Cap. And per the experience described above with the HGST SAS 6 TB drive (but ironically not also the He 6 mentioned) was repeated in mine, inasmuch as the He8 mounted fine after a restart from Snow Leopard. Not from Mavericks or later.

So, be warned that at least some of the HGST 8 TB mechanisms will not mount on restart either. (It's possible that the ones OWC is shipping right now do, but I wouldn't buy one without being certain it had been tested in a 4,1 and a 5,1.) But wait: HGST and the industry have an even worse trick up their sleeve (indeed the first issue may be mostly Apple's fault, hard to say). It's called Power Disable Feature, and any drive with it (introduced in half of the part numbers in the He10 family from HGST of 8 and 10 TB SATA helium drives) will behave like a brick in any of these machines and many, many more. The feature takes voltage on Pin 3 of the SATA connector above something like 0.7 or 1.5 volts, I forget, to mean that the drive should please shut down now. Nearly all of the legacy SATA connectors have 3 volts on Pin 3, so no dice. The Voyager Q that I use (one capable of working with drives over 2TB) does not have power on Pin 3, as indicated by the fact that the nice new HGST He10 10TB drive that I bought <did> work in the Voyager, so it's being relegated to cloned backup use. Google "Power Disable Feature" to see the HGST PDF page detailing which half of the 24 different He10 part numbers have the feature and which don't. OWC just this week has added the best of those 24 parts to their stable for a lower price than the 8 of the older He8 family. The SAS drives may all have the feature, not sure. From Seagate, the pattern seems to be that the SAS 10TB drives have the deadly feature but the SATA 10TB Helium drives, at least the two which OWC sells, do not have it. And they also don't have the restart problem. And contrary to the specs, they are quieter than Hitachi's 10 TB He drives too. I was unable to determine whether the "right" version of the HGST 10TB Helium drive would mount on Restart, since it couldn't mount at all (internally).

HGST has said in their article that they'll be adding the Power Disable Feature to more drives in the future. It's thus possible that every 12TB mechanism they make will have it. I sure hope not. It's an optional feature of the SATA 3.3 spec. So far I've been unable to find a single external enclosure which is intended to express awareness of this feature by intentionally avoiding voltage on pin 3, let alone supporting the power-down command with variable voltage on pin 3.

UPDATE: I have just updated to High Sierra, which required a firmware update on Mac Pro.

The problem still exists as described in my initial post.

I have learned to live with avoiding a Restart, or shutting down and turning the computer back on each time I install new software that requires a restart after installation ...sad but true.

Thank you. Could you remind us which model of Mac Pro you updated to High Sierra?

So far, I'm happy with the Seagate 10 TB Helium drive, model number ST10000NM86 in my 4,1 with El Cap. I wish I'd waited just another week to be able to buy a Seagate 12TB helium instead for only $70 more just for the capacity.

Hi Joseph

My Macs are mid 2010, Dual 2.93GHz 6 Core, 56GB RAM (6x 8GB and 2x 4GB ECC DDR3),

Crucial M550 SSD (running OS High Sierra)

The only differences between the two Macs are in/how some of the additional drives are mounted.

One of my SSD’s use a spare drive bay, the other Mac has the same type SSD mounted using an Accelsor S PCI Card.

The drives that won’t mount are Western Digital 4TB Black WD4004FZWX HD’s.

****, they have 12tb single HD’s now.

Hobbyist have posted instructions on how to use a simple hack application to copy the firmware from a 5,1 onto a 4,1. Once you do that, your Mac seems to behave a lot like a 5,1 and to be able to be updated to High Sierra, and appears to accept the next firmware update do get there, with no known ill effects.

We are not allowed to post the explicit instructions here on Apple's forums, but it is not too hard to find. Of course if you do something like that, you do it for your own personal use and at your own risk.

Here's another data point. I just got bitten by this after purchasing 3 HGST 6TB NAS drives to replace some 4TB drives in my systems.

1. They do NOT mount after a restart. Do DO mount from a cold start. This is when they are installed in either of my Mac Pro 2012 5,1 machines. SAME behavior when they are mounted in one of my old ProMax eSATA enclosures.

2. HERE is the interesting thing. They DO mount reliably when they are in my OWC Mercury Elite Pro Dual enclosures, connected via USB, whether it's via the slow and old Mac Pro USB or the latest USB, via my MacBook Pro. So, whatever else may be in play, interface is one of the things at work here.

3. I have not tried booting from an HGST 8TB drive yet, but I am planning to install a Toshiba 6TB drive later. From all I have read, it should work, but I'll wait and see.

Another data point: the HGST 6TB NAS drive DID mount in an OWC 4 Drive enclosure attached to my MacBook Pro connected via Thunderbolt cable.

I'm convinced that it's an interface issue. SATA and eSATA don't work with these HGST 6TB drives.