macOS could not be installed on your computer

[Alicecasey]

A month ago, I changed the password to my MacBook Air and then forgot it, I went into recovery mode and I don't know how but I deleted my macintosh hd drive, whenever I tried to reinstall it said there was an error today I tried to reinstall sierra in internet recovery mode and it said macOS could not be installed on your computer. What can I do or will I have to pay £60 to get it fixed

 

[011]

Try with recovery mode and format SSD to be Mac OS Extended (Journaled) and install Sierra from the bootable USB drive disk.

 

[Fishrrman]

MacConfucious say:
User who puts password she can't remember onto MacBook, may discover that MacBook can't remember her..."

Did 011's reply above help you?

If not, what you really need is a USB flashdrive with a bootable copy of the OS installer on it.
Do you by any chance have access to another Mac?

If the answer is yes:
- Download a fresh copy of Low Sierra. I think you can get it here:
https://itunes.apple.com/us/app/macos-sierra/id1127487414?ls=1&mt=12
- Get a USB flash drive 16gb
- Download the free little app "Boot Buddy":
https://sqwarq.com/boot-buddy/
- Use BB to create a bootable flashdrive installer
- Boot from the flashdrive (hold down the option key at boot until startup manager appears, then you can choose it)
- When you get to the installer, QUIT IT for the moment
- Open Disk Utility
- ERASE the internal drive. Choose HFS+ with journaling enabled.
- Now quit Disk Utility and re-open the installer
- Let the installer install the OS on the internal drive.

That should do it (the install will take a little time).
If the answer is "no", there's another way.

 

[011]

Those answers are the best one , you wrote very detailed instructions for the same thing i was writing