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Cannot Recognize HDD for Formatting
#52729 10/22/19 08:08 PM
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MG2009 Offline OP
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Recently I did an erase of the internal HDD on the iMac - planning to clean install upgrading from Mojave to Catalina. (I have done a clean install with every upgrade, so the process is not new to me.)

I did the erase . . . then trouble. The HDD cannot be found when trying to install the new OS. Only the SSD (fusion drive) shows up as an option. The HDD appears in Disk Utility, but as "uninitialized." Any effort to erase and reformat leads to error messages. Partition option is greyed out.

I went to Terminal. Tried to erase and reformat from there, but get the error message: "Cannot write to the end of blocks."

So . . . Is there any way I can FORCE the HDD to be detected and reformatted . . . ready for the Catalina install? Some other 3rd party tool? Note: I tried DoYourData Super Eraser, but it does not recognize the HDD on the computer, only the SSD (fusion).

Any solutions out there?


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52730 10/22/19 08:30 PM
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I have heard of this happening in the past but it has been a long time and I have no idea how or why it happened but it would appear the SSD and HD components in your fusion drive have become disconnected. I found this article on creating a fusion drive from back in 2014. I have performed the procedure in both directions and it is not difficult — copying and pasting the commands goes a long way toward avoiding any errors. Hopefully the same commands are still in MacOS. (I would check but my MacBook Pro succumbed to the swollen battery syndrome and is in the shop so I am working on my iPad.)


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Re: Cannot Recognize HDD for Formatting
joemikeb #52731 10/22/19 09:46 PM
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I can't locate the thread, but didn't the same question come up a few months back?

I think How to fix a split Fusion Drive - Apple Support provided the answer.


The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire
Re: Cannot Recognize HDD for Formatting
joemikeb #52737 10/23/19 08:29 PM
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Thanks, Joe.

I tried the method as provided in your link. It all looked like it was going to work. The SSD "reset" went as expected. However, Terminal stated that the HDD could not be "unmounted." So I did a "force unmountDisk" command in Terminal, and got the message that the unmounting was successful.

BUT . . . when I went back to re-do the drives, I again received the could not unmount the HDD message even though Terminal's log stated that the unmount had been successful.

So . . . I will try Artie's link and see how that goes. Fingers and toes are crossed.


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52738 10/23/19 11:20 PM
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Gave the second link a shot.

Again . . . all looked good to start with.

Terminal reset the SSD just fine as APFS, by default. There is a message, though, saying that the HDD "cannot be written to the last block" (so nothing happens). Process Failed.

In recovery mode, the HDD shows up in Disk Utility as "disk3" (I TB). The SSD shows up as "disk0s2" (200 GB). The DU states that the HDD is "uninitialized" - which was a new term for me. Partitioning is greyed out. Any attempt to erase or rename causes a error message stating that the HDD cannot be unmounted. However, the First Aid runs for the HDD and states that everything appears to be okay.

Any ideas to "initialize" or force action on the HDD? The iMac seems to recognize the existence of the HDD, but I cannot do anything with it. Is there a 3rd party option to get the HDD (re) formatted and recognized (fixed?) . . . and able to have data written to the last block?

P.S. When Terminal is run, it looks as though the process on the HDD gets to the 50% mark (?) and then fails (and shows the "cannot write to last block" message.)

Last edited by MG2009; 10/23/19 11:33 PM. Reason: P.S. added

Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52739 10/24/19 12:13 AM
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I assume you are booting from the Recovery Drive partition on what was the Fusion boot drive? If so you might try booting from the Internet Recovery Drive. To boot from the Internet Recovery Drive power down completely, then boot while holding down Command+Option+R (it is Option key that makes the difference). You will first be prompted to logon to a network for internet access and then you will eventually be presented with essentially the Recovery Drive menu you would get booting from the Recovery Drive on your boot drive.

You will, of course, have access to a full version of disk utility and should be able to perform the same operations you were attempting, but there should be nothing open on either the HD or SSD portions of your Fusion drive. I don’t know this will work for sure, but it is certainly worth trying. Good luck 🍀


joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52740 10/24/19 06:31 AM
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Thanks. I rebooted into recovery - adding the Option key.

Same deal: code 69760 . . . unable to write to the last block of the device. You cannot erase the boot disk. Ownership of the affected disk is required.

Any others ideas?


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52741 10/24/19 01:20 PM
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As an old friend used to say, “Hecky darn!” I had really hoped that would work. The Option+Command+R boot should have eliminated any boot drive issues — at least in theory.

The only remaining idea I have is a Genius Bar appointment at the nearest Apple Store. They will have an external drive they can boot your Mac from which should unquestionably take any “you cannot erase the boot disk” question out of the picture.


joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52742 10/24/19 03:04 PM
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Me, too. Fingers and toes were crossed.


:0)


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52743 10/24/19 05:37 PM
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FWIW I have another suggestion for your consideration. Since the Fusion drive has come apart, rather than trying to put it back together, you might leave the HD and SSD as separate drives. Previously you mentioned the SSD is 200GB and that is more than ample space for a boot drive. (MacBook Airs come with 128GB SSDs).

Do an Option+Command+R install of MacOS on the SSD (that will be the latest version of MacOS compatible with your computer). Format the HD either as APFS or MacOS extended (MacOS extended is a bit faster on rotating rust but APFS is so much more flexible) then follow these instructions to move the User folder from the SSD to the HD. (Ignore the part about it having to be formatted MacOS Extended this will work just fine with either APFS or MacOS Extended).

By having the boot system on the SSD you will get optimum system performance at the cost of being a bit slower with large file access, but you may not even notice the difference. I did essentially the same thing with the Fusion drive in an old Mac mini several years ago and that Mac mini still works for me today as a file and printer server. I now have three separate APFS volumes on the HD sharing the same 1TB HD’s capacity. (In my opinion, APFS volumes beat the heck out of partitions for usefulness and flexibility,)

It won’t put the Fusion drive back together, but it will get you back up and running again. By-the-way, you could even install a bootable copy of MacOS on one volume of the HD to have around in case of a future emergency.


joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52745 10/24/19 09:54 PM
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Freelance’s question about how big an SSD is needed is of sufficient interest that I split it off and moved it to Mac Desktops and Notebooks.



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Re: Cannot Recognize HDD for Formatting
joemikeb #52753 10/25/19 09:57 AM
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Originally Posted By: joemikeb
(In my opinion, APFS volumes beat the heck out of partitions for usefulness and flexibility,)

I've been a partition guy since the day I learned about the possibility - Nope! Never ran into a space issue. - but I'm totally with you on APFS volumes!


The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire
Re: Cannot Recognize HDD for Formatting
joemikeb #52768 10/30/19 03:00 AM
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Re: Format the HD either as APFS or MacOS extended

But that is the exactly the problem . . . being unable to access the HD to do anything with it by way of erasing, formatting, partitioning, etc.

Re: Cannot Recognize HDD for Formatting
MG2009 #52769 10/30/19 03:01 PM
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I have been doing some more research and THINK your issue is arising at least in part because of a change that has occurred in hoe MacOS handles Fusion Drives. Originally Fusion Drives were created using Apple's core storage technology. But Apple has since dripped core storage and in current versions of MacOS they are supporting Fusion Drives through APFS. I have no clue why the Fusion Drive came apart in the first place but it occurs to me your current issue MAY be the result of some fragments of core storage format remaining on the drive.

IF that is the case your problem MIGHT be solved by intentionally separating the Fusion Drive to remove any remaining traces of Core Storage formatting. This Lifewire article is the most current I have found on how to do that. Hopefully after that you will be able to either put your Fusion drive components back together using APFS tools or, as I already previously suggested, leave them as separate drives with the SSD a dedicated System Drive and the HD as your Data drive. 🤞🤞🤞


joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52770 10/30/19 04:11 PM
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THANKS for all your help. You certainly are making much effort on my behalf and it is very much appreciated.

Unfortunately . . .

--------------------------------------

1. But Apple has since dripped core storage

That makes sense since one of the earlier "core storage" commands I tried using Terminal indicated that core storage could not be found, etc. (or words to the effect);

2. and the HD as your Data drive

I would be happy to leave the SSD for the OS and the HDD separate for the DATA . . . However, the HDD cannot be used AS IS. It cannot be formatted or written to because it "cannot be written to the last block" and any attempt at formatting or erasing "fails."

My issue is trying to get the computer to use the HDD. Disk utility shows that the HDD exists, but I cannot do anything with it. DU says that the HDD is "uninitialized." Also, I get a message at startup that "something" has not been initialized on the computer and I am given the option to click on a box marked "initialize." But when I do so, nothing appears to happen . . . at least the HDD has not changed or become available for use.

Quite the riddle to me. confused


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52771 10/30/19 04:39 PM
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Originally Posted By: MG2009
I would be happy to leave the SSD for the OS and the HDD separate for the DATA . . . However, the HDD cannot be used AS IS. It cannot be formatted or written to because it "cannot be written to the last block" and any attempt at formatting or erasing "fails."

Which is why I suggested intentionally breaking the already broken Fusion Drive on the theory that might resolve the issue preventing the HDD from being initialized. It is one of those it can't hurt and might help procedures and would only take a few minutes to try. There are two keys to doing this successfully
  1. Be sure you are booted from the Internet Recovery Drive
    • Option+Command+R
    • You are prompted to log onto a network
  2. you enter the commands exactly as shown in the article


joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52772 10/30/19 04:50 PM
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Ahhh . . . I hadn't caught the "breaking the already broken" idea.

I will try this later since I just installed CATALINA on the SSD and it will all be erased again through the process "breaking the broken" drive(s).

The procedure in the link you provided takes seconds, BUT the re-install of the OS takes about 45-60 minutes. I may even consider going back to MOJAVE since CATALINA does not recognize a dozen 3rd-party apps I like to use (i.e. I get the icon with the slash through it showing that it will not function with the most recent OS).


** This is the message I get in Terminal if I try to locate Volume Groups (as per the article) using "diskutil cs list" :

No CoreStorage logical volume groups found

Last edited by MG2009; 10/30/19 05:06 PM. Reason: added CORE STORAGE

Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52773 10/30/19 06:10 PM
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Originally Posted By: MG2009
The procedure in the link you provided takes seconds, BUT the re-install of the OS takes about 45-60 minutes. I may even consider going back to MOJAVE since CATALINA does not recognize a dozen 3rd-party apps I like to use (i.e. I get the icon with the slash through it showing that it will not function with the most recent OS).

It is times like you are going through that a good bootable external clone is so good to have around. One of those things you hope you never have to use but if they are ever needed they are invaluable.

As to those dozen third party apps, if they haven't been upgraded to 64 bit — which is what makes the broken — they are almost certainly no longer supported and they are overdue for replacement. Murphy's law and McGillicuddy's corollary still hold true. They will fail and at the worst possible time. Long experience indicates it is time to let them go and move on.


joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52775 10/30/19 06:40 PM
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Not sure what the CLONE would do to get the HDD up and running. I have all my data backed-up with Time Machine on Time Capsule as well as an External Hard Drive.

Which leads me to Plan B . . .

Is it possible to use the old Time Capsule drive as a regular HDD? Can I reformat it to work as an external hard drive? That is, plug it directly into the back of the desktop with an ethernet cable (not Wi-Fi) and not use it for a back-up anymore (i.e. as a replacement for the internal HDD I cannot get working)?


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52778 10/30/19 11:49 PM
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The clone could work as your boot drive until you solve the problem with your Fusion drive.

Yes you can plug your Time Machine Drive into the back of your computer and use it as a disk drive. You could even put your User folder on it following these instructions. You cannot however use it as the HDD portion of a Fusion Drive — that is not supported by Apple for numerous reasons.


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Re: Cannot Recognize HDD for Formatting
joemikeb #52781 10/31/19 06:35 AM
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Sounds like a plan.

The article seems clear enough to me (and I am NO pro).

The SSD becomes/is the bootable drive and will have a TEST/SPARE home folder. The Time Capsule EXTERNAL HDD will replace the INTERNAL unusable drive which came with the computer. That will just lie there until I can figure a way to get it up and running - if at all possible.

My User Home Folder can be moved to the (former) Time Capsule - as per the instructions - and I will always have it connected to the desktop when I do start up. Seems simple enough.

Presumably, I should erase and format the current Time Capsule to now become my main EXHD. Any special advise for doing so? OS Extended Journaled (according to the article) OR APFS? Further, I may get the internal HDD functioning and someday want to revert back to using the Time Capsule again for Time Machine backups.

Thanks, again, for all your help. In the short term, this looks like a good plan. I have 1 TB external HDD I currently use as backup. I also just bought a 2 TB external HDD to use for a second Time Machine backup.

:0)


Many thanks,
MG2009
Re: Cannot Recognize HDD for Formatting
MG2009 #52782 10/31/19 12:54 PM
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Yes you would need to erase the former Time Machine drive and you could use either MacOS Extended or APFS. (Don’t worry about reverting to using it for Time Machine you would want to erase/reformat it again anyway.) MacOS Extended would be a touch faster than APFS, but APFS is so much more flexible because of its ability to add and delete volumes quickly and easily and although the total storage of all APFS volumes cannot exceed the capacity of the drive, any single APFS volume may use the entire capacity of the drive. Ie. APFS volumes can grow or shrink as needed.

It sounds as if you have arrived at a functional work around.



joemikeb • moderator
Re: Cannot Recognize HDD for Formatting
joemikeb #52786 11/01/19 02:59 PM
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Dr. Joe:

Here is what I have done with the "old" Time Capsule (plugged into the back of iMac with ethernet cable):

1. Erased using AIRPORT UTILITY
2. Reformatted/Renamed in APFS using DISK UTILITY. Successful and shows device: Drive with Container and one Volume in APFS (renamed as EXHDD 1). First Aid run shows all is OK with disk.
3. Restarted computer and EXHDD 1 appears on desktop. :0)

Results (and problems) . . .

a. Amber light continues to flash when connected or not connected with the ethernet cable to the iMac

b. While plugged into the iMac with the ethernet cable, NETWORK SETTINGS in System Preferences indicates an internet connection. However, SAFARI will launch but no "Server is found." When the ethernet cable is UN-plugged from the computer, the internet (and Safari) function as expected.

It would seem the when the "new" EXHDD is connected via the ethernet cable, it interferes with the internet connection in some way. Any fix for this since, naturally, I want to be able to use BOTH the internet AND the new EXHDD (as the replacement hard drive for the original internal hard drive which is not working properly) at the same time?

And, of course, I want the EXHDD and the Internet to play well together before I move my Home Folder from the SSD on the iMac to the new EXHDD (then following with moving my backed-up files to the new EXHDD).

Any ideas?


Many thanks,
MG2009
Cannot Recognize HDD for Formatting
MG2009 #52801 11/02/19 04:49 PM
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I have inadvertently led you astray. You talked about your Time Machine drive and I had assumed (as in making an ASS out of U and ME) you were referring to an HDD in an external USB or firewire enclosures attached to you computer. Now I find that it is an Airport Time Capsule which is a Time Machine drive, but a special implementation of the technology as it is accessed as a SERVER resource through the CPU in the Time Capsule.

So, as you discovered it has to be formatted using the processor in the Time Capsule and that server knows Diddley about APFS so that is out of the equation. You can use it as a data storage drive but it will be SLOW. I do not believe you can move your User folder per. se. to that drive either. If you have the Time Capsule connected to your Mac via an ethernet port, your Mac does not need to connect to your WiFi, because it is physically connected to the Time Capsule and shares the Time Capsule's Internet connection and connection to any other devices logged onto TC's WiFi network.

My apologies for not getting back to you sooner, but I had major surgery Friday morning and a bit distracted and/or unconscious in the interim.


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ReCannot Recognize HDD for Formatting
joemikeb #52802 11/02/19 04:58 PM
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You somehow changed the title of this thread to "ifs."


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