Good Day
I am having iMac (21.5-inch, Mid 2011) - Model : A1311 , I want to tis iMac for online search, am installing macOS High Sierra from a bootable usb , the installation is going through until its gave me this error disk is lock. I tried to erase disk, tried to make a new partition but its just giving errors disk cannot be unmounted.
Please help
Quinton.
You should be able to use the Disk Utility in Internet Recovery Mode to Erase and Reformat the Internal drive.
see > Use Disk Utility to erase an Intel-based Mac - Apple Support
(try formatting Mac OS Extended (Journaled) instead of APFS)
Then you should be able to Install the offered OS X while in macOS Recovery Mode.
If the offered OS X is not High Sierra, install it and then Upgrade to High Sierra when you are up and running.
You should be able to use the Disk Utility in Internet Recovery Mode to Erase and Reformat the Internal drive.
see > Use Disk Utility to erase an Intel-based Mac - Apple Support
(try formatting Mac OS Extended (Journaled) instead of APFS)
Then you should be able to Install the offered OS X while in macOS Recovery Mode.
If the offered OS X is not High Sierra, install it and then Upgrade to High Sierra when you are up and running.
You can not erase the disk that you are started up from.
You need to startup from the USB installer and then reformat the iMac's internal ST3500418AS Media drive.
Note: You can also startup from disc 1 of the original gray install disc set that came with that iMac and erase the internal ST3500418AS Media drive.
1) It looks like the High Sierra Installer is on the internal drive and can not be used.
2) The Installers on the external drive and base system are older and can not erase the APFS format.
With that in mind:
Create a new bootable High Sierra Installer on a flash drive.
see > Create a bootable installer for macOS - Apple Support
Startup from the flash drive and erase internal drive.
Then go back and reinstall High Sierra from the flash drive.
I think the confusion is coming from the Install macOS High Sierra named partition on the internal drive.
You need to startup from Install Mac OS on the External Drive or the OS X Base System (aka the Recovery partition) and then erase Internal drive.
Hi,
If you have TimeMachine or any other backup, you should reformat as APFS whole drive from the scratch then restore the data from TimeMachine or other backup since it seems your partitions are MacOS extended Journaled and the other partition is APFS format.
In MacOS Utilities > Select Disk Utility > then select and rase the internal ST3500418AS Media drive.
see > Use Disk Utility to erase an Intel-based Mac - Apple Support
Then go back to macOS Utilities > select Install macOS and Install the macOS.
The Install macOS High Sierra Installer is on the Internal drive and can not be used.
Shutdown the iMac by holding the power button for 10 seconds.
Then startup the iMac holding the Alt (option) key.
Select the 5.13GB Install Mac OS X disk,
or macOS Recovery if available.
Shoot us a screenshot of the Drives listed in the Disk Utility sidebar.
Hi, I did do the :Shutdown the iMac by holding the power button for 10 seconds.
Then startup the iMac holding the Alt (option) key.
Select the 5.13GB Install Mac OS X disk, then the Install MacOS High Sierra disk appears , I click it and then the apple logo appears , after that the MacOS utility screen appears, I try to install and tried to erase , but same error. As I reminder the iMac had MacOS X Loin on and than did Hold Alt + R and did a recover install ,after that it shows High Sierra installed. I don't why the it does want to install,
The one using the supplied High Sierra terminal command.
Another option, take the iMac to your local Apple Authorized Service Provider and have them erase and reinstall High Sierra.
see > Find Locations
HI
Den.thed/ Kaz-k
I do not have a TimeMachine, or any other backup, I am new to Apple , I received the iMac from my cousin. The is my first screen when startup , the Apple log screen , then the funny white boxes, the MacOS Utility Screen.
so I do not have any backups, just want to do a clean install. I do understand that I cannot erase the drive that I startup with. I do have a usb bootable that I use to install the OS. Did try to startup with usb , Other thing I am using windows keyboard not apple keyboard.
by using this :
Turn on the Mac, then immediately press and hold the Option (Alt) key. Release the Option key when you see a dark screen showing your bootable volumes, including the bootable installer. Select the bootable installer. Then click the onscreen arrow or press Return.
I tried this option but my iMac is just booting into the macOS Utilities screen.
How do I bootup to an other USB , I only have the bootable usb .
Thank you.
Hi, Den
My problem is I stay in a small town, their are no Apple support suppliers, I am olmost 1000km from a supplier to give me IMac in for repair, I spole to my cousin that gave me the IMac, he say the he erase the harddrive before he gave it to me. So he Said that he erase the harrddrive and it did not complete erasing, so the process was incomplete. So I received theirac like that and all I did was :
I did hold command R and did a recover install over internet, after that it show High Sierra install, I believe the install and the erase was not done properly. Is there no other option that I can erase disk under Terminal, example. Just until I managed to take the imac to a apple supplier near to my town,,
Thank you.
I appreciate your help.
Good Morning,
Den.thed
Hope you doing well .
I managed to install macOS High Sierra on a External Hardddrive , so I startup on external drive under disk utility I managed to erase the Internal Hardddrive, so now I want to install the MacOS High Sierra on the Internal Hardddrive how do I do that while I am in OS or must I boot up with USB stick again. See pics attached.
Thank you.
Hi, I did just as you said and and erase drive but it gave me this error , couldn't unmount disk, operation failed.
HI, Den.Thed
Please find attached pics of Disk list in Disk Utility.lease find attached picture of my Drives listed in Disk Utility.
The Partition cannot be resized, Operation failed- Disk is Locked.
