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User profile for user: ipbloke
ipbloke Author
User level: Level 1
10 points

Error -69877: Couldn't Open Disk

Hello


I am really struggling to fix a problem I seem to have created after trying to help a friend install Windows 10 using Bootcamp (after he complained that BootCamp assistant would throw an error stating it couldn't locate a Windows partition.


Effectively the issue is that I seem to be stuck with my main HDD formatted in Windows NTFS and unable to erase the disk (using 'DiskUtil' in Mac Recovery Mode) as it throws an error:


(-69877: Couldn't open device)


The Mac is a 2015 Model 32GB iMac which has a 1TB HDD (disk1) and SSD Drive (disk0)


diskutil list



diskutil info disk1



diskutil info disk1s1



Here it looks like the disk has been successfully unmounted


diskutil unmountDisk force disk1


I then try to erase disk1 however this throws up the aforementioned error code -69877


diskutil eraseDisk apfs MAC-HD /dev/disk1



From the above, it's just not clear what my next move is, as I have tried to remove the disk volume (disk1s1) separately to no avail & I have also tried to re-partition disk1 using a different format:


diskutil partitionDisk /dev/disk1 GPT APFS MAC-HD R



If anyone has any suggestions on what I could try next to resolve this, I would be externally grateful.


Thanks in advance


Matt



iMac Line (2012 and Later)

Posted on Mar 24, 2022 2:17 PM

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User profile for user: ipbloke
ipbloke Author
User level: Level 1
10 points

Posted on Mar 25, 2022 5:34 AM

Hi


The issue here (in my experience) is that installing Windows 10 using Bootcamp simply doesn't work when running MacOS Monterey.. This seems to be a common thread from what I can make out in which the default answer is to run MacOS Catalina instead if you want to successfully install Win 10.


Having just completely reinstalled MacOS Monterey using Recovery Mode, (then checking disks for errors, making sure Time Machine is disabled, ensuring no external drives are connected), it seems running Bootcamp Assistant for the first time and trying to install Windows 10, still fails & throws up an error that Windows 10 cannot locate the disk and partition that has been designated (BOOTCAMP Partition)..


Happy to explore different ways to achieve this if I am missing something here..



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User profile for user: ipbloke
ipbloke Author
User level: Level 1
10 points

Mar 25, 2022 5:34 AM in response to PRP_53

Hi


The issue here (in my experience) is that installing Windows 10 using Bootcamp simply doesn't work when running MacOS Monterey.. This seems to be a common thread from what I can make out in which the default answer is to run MacOS Catalina instead if you want to successfully install Win 10.


Having just completely reinstalled MacOS Monterey using Recovery Mode, (then checking disks for errors, making sure Time Machine is disabled, ensuring no external drives are connected), it seems running Bootcamp Assistant for the first time and trying to install Windows 10, still fails & throws up an error that Windows 10 cannot locate the disk and partition that has been designated (BOOTCAMP Partition)..


Happy to explore different ways to achieve this if I am missing something here..



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User profile for user: ipbloke
ipbloke Author
User level: Level 1
10 points

Mar 25, 2022 4:22 AM in response to Jack-19

Hello Jack-19


Thanks for replying.


I am unfortunately unable to boot into MacOS now to run DiskUtil from a GUI, as the main HDD no longer has MacOS installed (due to the aforementioned issue wiping the entire disk contents).


If I try to perform a MacOS recovery & install either the lastest MacOS (Monterey) or the OS that was shipped with Mac) then it cannot locate the main HDD (it can only located the SSD which is 24GB) so not large enough.


Anyhow - I think I have solved this so i'll try to articulate what I found after finding a clue from a post online:



Source: https://www.tonymacx86.com/threads/trying-to-fresh-install-from-bootable-usb-getting-disk-utility-error-69877-couldnt-open-device-when-erasing-ssd.319501/


Effectively, the issue here is that if you are booting into MacOS recovery mode over the internet, there are 3 x restore options to choose from:


  • Command-R: Start up from the built-in macOS Recovery System. Use this key combination to reinstall the latest macOS that was installed on your system, or to use the other apps in macOS Recovery.


  • Option-Command-R: Start up from macOS Recovery over the internet. Use this key combination to reinstall macOS and upgrade to the latest version of macOS that’s compatible with your Mac.

  • Option-Shift-Command-R: Start up from macOS Recovery over the internet. Use this key combination to reinstall the version of macOS that came with your Mac or the closest version that’s still available


Source: Use macOS Recovery on an Intel-based Mac - Apple Support (QA)


The issue for me is that when I opted to recover using options 1 & 2 above, running diskutil in recovery mode will not format / erase any windows based partition (and throws up error -69877: Couldn't open disk).


When I opted to recover using the 3rd option (reinstall the version that came with the Mac), I was able to successfully run diskutil and erase the windows_NTFS partition from disk1:


Syntax: diskutil eraseDisk JHFS+ "Name of Disk" diskID (no quotes to be used here)


I ran this: diskutil eraseDisk JHFS+ HDD disk1


This then successfully formatted disk1 and did not produce the aforementioned error.


As the original post I found online seems to imply, it seems Apple has done something and changed the recovery installer within Monterey so that you can no longer nuke (format) any windows formatted partitions..


In case anyone else has the same issues, here is a summary of what I did:


  1. Boot into MacOS recovery mode using: Option-Shift-Command-R: This starts up macOS Recovery over the internet. Use this key combination to reinstall the version of macOS that came with your Mac or the closest version that’s still available
  2. Once MacOS recovery has loaded, you don't need to actually install the old version of MacOS that came with your mac. You just need to select and open 'Terminal' for the menu bar at the top of the screen.
  3. Using Terminal, run diskutil to identify / unmount the disk / partition that has been formatted (see my screenshots as the original poster)
  4. Proceed with caution and run diskutil to format the disk you want to format: diskutil eraseDisk JHFS+ "Name of Disk" diskID
  5. You should find that you can now successfully format that partition without it throwing error -69877.
  6. Exit the terminal once complete and restart your Mac.
  7. Boot again into MacS Recovery mode using the first option I provided above (the key combination to reinstall the latest macOS that was installed on your system).
  8. Select the latest MacOs (Monterey for me) to reinstall as your MacOS system.
  9. Your Mac should now correctly identify and display the hard disk that you want to re-install MacOS to.


A bit long winded however this '-69877: Couldn't open Disk' error caused me some pain figuring out why I could not wipe a Windows based (NTFS) partition


Matt


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User profile for user: PRP_53
PRP_53
User level: Level 10
91,705 points

Mar 25, 2022 4:55 AM in response to ipbloke

Adding Windows 10 to an Apple Computer should be done on Qualifying Apple Computer using Bootcamp Assist or via a Compatible VM Software.


Removing a Windows Installation partition should also be done using the Bootcamp Assist to avoid such issue as this computer is experiencing.


Added - this computer appears to be using a Fusion Drive which adds another layer of complexity especially when Windows is added to the mix.


Once may be able to recovery from this issue.


To perform this action will require booting from a Bootable Installer. 


The below steps will WIPE ALL DATA from the Drive and there is not recovery - period.


This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer.


Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.


Special Notation: How to fix a split Fusion Drive


1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.


2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 


3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives. 


4 - Choose the Upper Most Drive ( not the volumes indented and list below ).


5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map. This applies to macOS 10.14 Mojave and above. 


5A - Formatting for macOS 10.13 High Sierra and below requires HFS Journaled with the GUID Partition Map


6 - Once that is done >> backup out of Disk Utilities and choose install macOS. 


7 - Follow the prompts and it may automatically reboot several time. 


8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.

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Error -69877: Couldn't Open Disk

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