How to Force Unmount Macintosh HD With Terminal You can use the Terminal app to force unmounted your Macintosh HD on a Macc machine. Note: This is especially beneficial when the disk does not respond to unmount streamlining orders. Here is an ultimate guide on how to do it the right way.
How to Force Unmount Macintosh HD
Open Terminal:
Applications >
Utilities > Terminal
Identify the Disk:
Enter the command:
bashdiskutil list
This will list all connected Disks and their Identities. You need to look for identifier for Macintosh HD (e.g. /dev/disk1).
Use the following command to force unmount
Enter the below command, replacing with your disk identifier actually
bash sudo diskutil unmount force /dev/
Press Return. If maybe asked for, type in the admin password.unmount (ad)
Verify Unmounting:
You should see this when the disk is really unmounted now:
bashdiskutil list
“Macintosh HD”, if exists as mounted，则删除成功
Troubleshooting Tips
When the disk could not ejected error message appears, it is because some applications or processes are still using the storage device. Which processes are accessing the disk
bash$ sudo lsof | grep /dev/
If you are unable to unmount them, simply close the applications or restart your Mac Recovery Mode as needed.
Additional Considerations
Back Up Important Data–Before you eject your disk by force, make sure to back up all important data from the drive because this might result in completely losing files especially if they are being written at that very moment.
Force unmount warning: This will work but be aware that might cause file corruption if there are active operations running on the disk.
With this foundation laid, you should be able to easily manage your Mac’s disks using Terminal commands, taking a more deterministic approach towards managing the storage of your system and not solely relying on GUI tools.