Help me getting OS Sierra installed after screw up while updating software

[rmoltu]

I am pretty new to Mac and I screwed up while updating my MacBook Air to macOS Sierra. When booting the Mac after the first restart in the installation, there was a 0-100 % installation bar and I accidentally pulled out the power plug to the Mac (the battery is not working). This resulted in what you call the "kernel panic".

After some searching I have found the recovery mode/menu and tried to reinstall macOS, but I get the message that my Macintosh HD does not have enough free space.

I then accessed the Disk Utility and tried to erase the Macintosh HD, but it failed. (maybe because I was in the middle of the installation wizard of OS Sierra?)

I am now trying to install macOS Sierra on an USB drive, but I do not know exactly what to do when this is done (if it works)... Is it possible to make some free space on my Macintosh HD so that I can install macOS Sierra from the recovery mode?

Is there anything else I can do to fix this problem?

 

[allan.nyholm]

Might I suggest Unmounting your Macintosh HD in the sidebar of Disk Utility whichever way you can access it?

Then go to the top level of the drive - it's usually a model number - then either erase the whole drive or look around in the partition section of Disk Utility and click away the partitions that might be there are create an entirely new one filling up the whole drive.

Usually I use the Terminal on the Internet Recovery partition for this procedure; CMD+ALT+R on boot and see what you can do. If you can get through to the Disk Utility program that way or the Terminal then you should be good to go.

You need to be on a different drive than the internal drive in order to format the Macintosh HD for instance. That's where the Internet Recovery suggestion comes in. You'll get which ever Mac OS that came with the computer and you should take that and have it install only to install macOS Sierra from the Mac App Store and begin again. Or create a USB drive with the installer for macOS Sierra and clean install from that USB.

diskutil list

diskutil eraseDisk jhfs+ "Macintosh HD" disk0

<- look on the list that scrolls through when using the first command and select your troublesome drive.

Your installation to the USB drive should work fine as macOS can boot from that too. And you get the OS and Disk Utility to play with after the initial launch.