My High Sierra install failed with can't create pre-boot AFPS file. I erased the SSD in disk utility but the only choice for a format is AFPS not OS extended journeled....how can I get disk utility to format other than AFPS because that is what is causing the problem in the OS High Sierra install. Thanks for the help
MacBook Pro 16″, macOS 10.15
When you open Disk Utility you need to click on View in the menubar and select Show All Devices.
This will now show the Disk and its Volumes.
When you want to erase your mac and reformat it then you need to highlight the Disk and not any of the indented Volumes.
The Disk will be called Apple SSD… or something similar. Only highlighting the Disk and clicking Erase will show you the full
list of options for reformatting.
Click Erase.
Give the Disk a name.
Format: MacOS Extended (Journaled)
Scheme: GUID Partition Map.
Click Erase.
When Done quit Disk Utility.
When you open Disk Utility you need to click on View in the menubar and select Show All Devices.
This will now show the Disk and its Volumes.
When you want to erase your mac and reformat it then you need to highlight the Disk and not any of the indented Volumes.
The Disk will be called Apple SSD… or something similar. Only highlighting the Disk and clicking Erase will show you the full
list of options for reformatting.
Click Erase.
Give the Disk a name.
Format: MacOS Extended (Journaled)
Scheme: GUID Partition Map.
Click Erase.
When Done quit Disk Utility.
If you have made a bootable USB flash drive correctly using Terminal and the createinstallmedia command
along with a valid copy on an installer app then yes it should have a copy of Disk Utility on it.
Pity you cannot remember which OS it would install, pug it in to your mac and simply double-click on its
icon on the Desktop to open it and see which installer is on it. If it is macOS High Sierra then boot to the USB
restart your mac while pressing and holding the option/ alt key. After a minute or two you will see the Startup Manager
select the USB and press Return.
When it boots up you will see the Utilities panel, select Disk Utility press Continue.
Or just boot to your Recovery HD.
Thank you, that answered my question....but the erase failed with the message: Unmounting disk, Couldn't unmount disk. Operation failed.
I ran first aid...said all okay, tried erase again....same result! Any ideas? Thanks
No....I did not know that, but obviously it is logical. I have a 8 gig flash drive I made a long time ago so I could boot up but don't know what operating system I was running when I made it....does that matter in this case/ and will it have a disk utility function....
THANKS
Well, I know the bootable flash drive was made before High Sierra so can I use the disk utility on it and still reinstall High Sierra or am I only going to be able to install the OS I made the boot disk for?
(not the flash drive) I booted to the menu that includes disk utility and reinstall and get help from the internet but confess the instructions for booting to Recovery HD are not clear....and it sounds like that is my only real option
thanks
So I looked at the flash drive and it is El Capitan. Can I use my other computer (this one) to make a another bootable flash drive version of El Sierra? And does that allow erasing the interior disk completely including the troublesome file system. I'm probably not calling the flash drive by the right terminology but that flash drive has to be set up for El Sierra I assume, the El Capitan bootable flash drive doesn't get it.
If you have another mac then it may be possible to make another bootable USB flash drive.
The ability to do this would be down to what model and year that mac is.
So can you tell me what mac model and year this 'donor' mac is, click on the top let of the
screen and click on About This Mac.
It would be useful to know the mac model and year of the original mac in question also.
Next you will need to tell me which OS you would like to reinstall on the original mac,
would it be Mac OS X El Capitan 10.11, macOS Sierra 10.12, macOS High Sierra 10.13.
El Capitan and Sierra use a different procedure that requires a mac that can actually run
El Capitan or Sierra. High Sierra downloads the install app directly.
Once you have given me the exact details required then I can give you precise instructions
on downloading the required OS and creating a bootable installer. And then installing the OS
onto the original mac.
I am communicating with you on my brand new 2019 model Macbook Pro 16, running Catalina. I am trying to load High Sierra on my late 2011 Macbook Pro, which has a non factory Samsung 500 gig SSD. I had been running OS El Capitan on the 2011 and had planned to remove the harddrive and use it as an external drive on the 2019 MBP but learned that it would have to run High Sierra for that to work and High Sierra is the latest OS a 2011 will run. I downloaded High Sierra and attempted to install it but the install failed because of the APFS file error message: could not create Preboot.....APFS. So I attempted to erase the disc and that failed because I was booted up to it....
So, I would like to install High Sierra on the 2011 so the drive would be the latest compatible, as ultimately the 2011 will go to wife or daughter. I have a time machine backup on another Samsung 500 gig SSD of my data that I will than somehow make into an external drive for the 2019 and have all my previous files without loading up the memory of the new 2019... thank you for your patience and help, it really is much appreciated. 40 years ago I was a wiz with DOS but it has been slowly downhill since with it all a bit less intuitive for me.
I owe you an apology, I realized this morning that when I got your notice of your message of the 9th by email I just hit reply in email and said thanks that was fine,...but obviously that email never reached you. Sorry it seemed like I was unresponsive, but not the case....
Eau Rouge, I hope all is well with you and you have not replied because you are unavailable and no longer in a position to help me. Should I not have any reply today, tomorrow I will put in a new request/question to the forum.
regards
Mex Raider
I take it you are using the Disk Utility available from your Recovery HD or a bootable USB.
You cannot erase the disk when you are booted up to it.
The flash drive is OS El Capitan
i will respond to you tomorrow if you do not mind, i am in the midst of something else.
For my time planning, any updated idea of when you might be able to reply? Thanks
disk utility format only has AFPS not extended journel choice
