MacBook Pro Disk Utility error 69842

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MacBook Pro Disk Utility error 69842

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is Disk Utility error -69842 hardware or … - Apple Community

I have been having trouble with this message coming up in connection with Time Machine backups getting clobbered, and failures in reformatting, all on USB drives.

In the case noted above, it was a software error in High Sierra beta version, which was then fixed. My problems now are with a MacBook Pro running Big Sur, which is 3 whole versions later, so a repeat of the same bug seems unlikely.

It's not a hardware problem with the drives, because the formatting problem does not arise on another Mac of mine (running Catalina, BTW; and when a drive is properly reformatted there, it doesn't work on my MacBook Pro). Also, it happens on drives from 2 different reputable makers, and also on an old 5 1/2 inch DISK drive that I revived for this test. Not a compatibility problem in the drives.

The diagnostics, both the easy kind and the ones that run on a D-reboot (recovery mode diagnostics) show everything perfect.

I am reluctant to upgrade to Monterey or Ventura on the weird tiny chance that it's a Big Sur software bug that somehow has been fixed in a later release; I'd rather try more with the evils I see than fly to others I know not of, as Hamlet would say.

I'm scheduled to take the thing in to the Mac Store for testing, but I'm curious to know if anyone has seen this in any recent version.

[Re-Titled by Moderator]

MacBook Pro 16″, macOS 10.15

Posted on Nov 20, 2022 12:22 AM

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Answer 1

Top-ranking reply

HWTech

Level 9

66,806 points

Dec 7, 2022 08:06 AM in response to Porlock Junior

Porlock Junior wrote:

This was an Option-Command-R-P boot, and he showed me how to do this with one's right hand, if one has large enough hands and a fat thumb. I regret to say that I didn't remember the name of the component that this refreshes; but it worked. BTW, pinkie finger on P, index on R, thumb pressing Option and Command - now use left hand to make it reboot. AND keep holding the weird key combination until the *second* time it goes BONG to announce that it is re-rebooting!

That is typically called a PRAM Reset (or NVRAM Reset) and only works with Intel Macs (or very old PPC Macs). The M1/M2 Apple Silicon Macs don't have the traditional special startup keys any more (all combined on a special boot menu).

Reset NVRAM on your Mac - Apple Support

That is a very odd thing to have this fix. Thanks for the update.

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Answer 2

a brody

Level 10

85,263 points

Dec 5, 2022 12:47 PM in response to Porlock Junior

Please note, issues with beta software need to be addressed directly with http://bugreporter.apple.com/

Disk Utility in general doesn't fail unless there is something wrong with the hardware when it comes to reformatting drives. Often what happens is that there is insufficient power for the external drive. USB-C does not power the drives unless you use a USB-C passthrough hub that uses the power cord for the computer to power the hub.

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Answer 3

Dec 5, 2022 02:03 PM in response to a brody

As to Beta, I mentioned that only to note that it's irrelevant to the problem, and because that was the first hypothesis that Mac telephone support came up with.

Yes, the problem is commonly hardware-based, which was the second thing Support came up with. Note that my first note here ruled out a disk drive (HDD or SSD) problem. As to a power problem because of a hub connection, that was ruled out by having the drive plugged directly into the computer's USB-C drive.

The real solution here came when I took the machine to the Apple Store. The tech who took my case was an experienced graybeard (not quite so gray as I am) who quickly noted the details, remarked on how unlikely this was, and then did a Recovery Boot, which fixed the problem, permanently and reproducibly.

This was an Option-Command-R-P boot, and he showed me how to do this with one's right hand, if one has large enough hands and a fat thumb. I regret to say that I didn't remember the name of the component that this refreshes; but it worked. BTW, pinkie finger on P, index on R, thumb pressing Option and Command - now use left hand to make it reboot. AND keep holding the weird key combination until the *second* time it goes BONG to announce that it is re-rebooting!

If you're in Marin County, consider taking your odd problem to Corte Madera.

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MacBook Pro Disk Utility error 69842

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