Problem erasing late 2009 iMac and restoring operating system

[janelux]

Using the instructions in the Apple Help section titled "what to do before selling or giving away your Mac.

I was able to erase the internal hard drive, but when I try to restore an operating system, it keeps trying to do Sierra, which is what I was running and it then has errors and will not do anything.

HELP!!! How do I resolve this?

Thanks so much for any assistance!!!

 

[Spawn_Dooley]

Just ensure you format the drive Mac OS Extended (Journaled).

In Disc Utility in the left column you will see your internal hard drive which will start with the size then a string of capital letters. Below, indented will be the MacintoshHD partition.

If you click on the MacintoshHD partition you should see the format information in the bottom left.

 

[iMav]

What is the specific error?