MacBook "loses" disk

Question

Level 1

69 points

MacBook "loses" disk

Running Sierra - following a reboot, one of two internal drives no longer shows up. It shows up in Disk Utility in Recovery mode - First Aid checks it out as ok. In normal mode, or safe mode, it doesn't show up in Finder and Disk Utility can't load info on any drives.........Tried removing DiskUtility.plist in Preferences. No difference.

All Mail and Spotlight indexing also lost.......

Will probably have to reload OS - which will solve it until the next forced reboot.

Any pointers appreciated. Thank you.

MacBook Pro, macOS Sierra (10.12.6), 8Gb Memory

Posted on Jul 31, 2018 1:27 AM

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Answer 1

Aug 1, 2018 10:10 AM in response to Robin Curtis

I had a problem (with a clean Sierra 12.6 install) similar to yours, which I posted about recently. Though it was fine at first, my internal HD just stopped being recognized on startup one day and became read-only, though it was fine in Recovery before the OS is started. Similarly, First Aid checked it out as ok, and it doesn't show up in Finder in Normal or Safe modes. Like you, I followed some of the advice here to no avail. My HD was not defective, and following some of the subsquent advice to "repair" it would have destroyed its data. I was also having weird but probably related (SIP?) problems with the OS giving me a warning about apps downloaded from the internet every time I booted my desktop, even though I clicked on those messages many times over. All of that is now gone after doing a second clean install of Sierra 12.6. (However, I had to reinstall twice, as the HD problem was not resolved after a regular non-clean install!).

Why this occurred is anyone's guess, and though I've reinstalled most of the programs I had on it, whether it will re-occur again after reinstalling all of the original programs, I don't know. I used a cleaning app to delete about 37mb of language files from the system, on the first go. I doubt that could cause what happened, but its the only thing I can think of that might muck something up. That, and using a small app to change the system font from "San Francisco" to "Lucida Grande". But, I changed it back, no difference.

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Answer 2

anonyme4321

Level 6

17,275 points

Jul 31, 2018 2:32 AM in response to Robin Curtis

In "normal mode" you can try to mount the missing drive using the terminal commands:

mount /dev/disk0

ormount force /dev/disk0if the first command doesn't work.

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Answer 3

Robin Curtis Author

Level 1

69 points

Aug 1, 2018 12:35 AM in response to anonyme4321

Restored the OS - (takes several hours). 2nd disk shows up in Finder again. Disk Utility loads information from both drives again ok. Mail and Spotlight indexing all carried out again.

Until the next time..............

Thanks for your pointers.

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Answer 4

anonyme4321

Level 6

17,275 points

Jul 31, 2018 2:06 AM in response to Robin Curtis

What is the output of "diskutil list" both in recovery mode and in normal boot?

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Answer 5

Eric Root

Level 10

685,257 points

Jul 31, 2018 8:48 AM in response to Robin Curtis

If you make a backup of the drive, preferably 2 on 2 separate drives, you can then repair the drive and restore the data. Not repairing it may cause you to lose the data if the disk becomes unreadable.

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Answer 6

Robin Curtis Author

Level 1

69 points

Aug 1, 2018 12:19 AM in response to Eric Root

Restored the OS - (takes several hours). 2nd disk shows up in Finder again. Disk Utility loads information from both drives again ok. Mail and Spotlight indexing all carried out again.

Until the next time..............

Thanks for your pointers.

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Answer 7

anonyme4321

Level 6

17,275 points

Jul 31, 2018 2:56 AM in response to Robin Curtis

diskutil repairDisk disk0

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Answer 8

Eric Root

Level 10

685,257 points

Aug 1, 2018 1:10 PM in response to Robin Curtis

You are welcome.

Check to make sure your applications are compatible.

Application Compatibility

Also check to make sure there is a compatible driver for your printer.

Do a backup before installing, preferable 2 backups on 2 different drives.

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Answer 9

Robin Curtis Author

Level 1

69 points

Jul 31, 2018 2:26 AM in response to anonyme4321

Thanks for responding.

This is when running in "normal mode" -

MacBook-Pro:~ robincurtis$ diskutil list

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *240.1 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_HFS 239.7 GB disk0s2

/dev/disk1 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *750.2 GB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_CoreStorage RHCMBPro750 749.3 GB disk1s2

3: Apple_Boot 650.0 MB disk1s3

/dev/disk2 (internal, virtual):

#: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS +748.9 GB disk2

Logical Volume on disk1s2

9C2E9CD9-1D05-4B7C-A76C-41C7C9F21CC7

Unencrypted

It is the first disk in the list that is "missing". ie the 240GB SSD. disk0

In this listing it does not have a name - in Recovery mode the name is displayed. Will post Recovery mode listing later - having to use machine during the day !

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Answer 10

Robin Curtis Author

Level 1

69 points

Jul 31, 2018 2:36 AM in response to anonyme4321

Thanks - these are the responses

1st attempt:

MacBook-Pro:~ robincurtis$ mount /dev/disk0

mount: /dev/disk0: unknown special file or file system.

then tried:

MacBook-Pro:~ robincurtis$ mount force /dev/disk0

mount: You must specify a filesystem type with -t.

Filesystem type ?

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Answer 11

Robin Curtis Author

Level 1

69 points

Jul 31, 2018 2:48 AM in response to anonyme4321

Many thanks - but:

MacBook-Pro:~ robincurtis$ mount /dev/disk0s2

mount: /dev/disk0s2: unknown special file or file system.

So - I tried:

MacBook-Pro:~ robincurtis$ mount force /dev/disk0s2

mount: You must specify a filesystem type with -t.

Still wants filesystem type ?

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Answer 12

Robin Curtis Author

Level 1

69 points

Jul 31, 2018 3:04 AM in response to anonyme4321

ummm.....maybe not.

MacBook-Pro:~ robincurtis$ diskutil repairDisk disk0

Repairing the partition map might erase disk0s1, proceed? (y/N) N

Repair canceled

Think I may have to take the safe option and reinstall OS. Don't really want to lose stuff on the drive.

No idea why this happens. Something floating around in my system that causes this - even after reinstalling OS.

Thanks for your efforts. Much appreciated.

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Answer 13

Robin Curtis Author

Level 1

69 points

Jul 31, 2018 9:09 AM in response to Eric Root

Eric - thank you again for replying.

I am very doubtful that the disc is damaged - it loads in Recovery mode and Disk Utility First Aid happily checks it out.

Somewhere / someplace in my "normal" Sierra boot script - something manages to lose track of the whereabouts and information relating to this disk - and only this disk. Whereupon Disk Utility can no longer load ANY information about ANY disks - despite the standard HardDrive showing up in Finder and being perfectly usable.

You have mentioned that it may be related to the DiskUtility plist in the past. Have tried removing it - no effect.

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Answer 14

Robin Curtis Author

Level 1

69 points

Aug 1, 2018 10:18 AM in response to Mayden Vane

Many thanks for your reply.

I suspect that the only way that I will get past this is by doing a clean install. There is something lurking in my system that causes this repeatedly. Apparently disconnected issues, ie failure to find disk related information, and losing all Mail & Spotlight indexing - both happen simultaneously. The other thing that starts to happen is failure to shut down properly, and /or restart properly, and or boot up properly. The system goes through the motions, hangs and forces me to do a hard shutdown - which probably messes things up even further.

Just going to have to take a day out, bite the bullet, and do a clean install. Probably of High Sierra - or might that be a step too far !!

Thanks again.

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Answer 15

Eric Root

Level 10

685,257 points

Jul 31, 2018 9:43 AM in response to Robin Curtis

You are welcome. I suggested what I did because the output of the Terminal command shows an error. Does Disk Utility do this when booted normally or when in the Recovery Partition?

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MacBook "loses" disk

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