Trying to reinstall OS but getting errors

[davesmith123]

I have managed to erase the disk but when I tried to reinstall the OS, I got an error "Could not create a preboot volume for APFS". Based on what I read online, I unmounted the disk and and then tried to erase it and reformat it into Mac OS Extended (Journaled). Then I keep getting an error "Erase process has failed" I've got not idea where to go from here!!

Please help. Thanks

See screenshots of what I'm currently able to see/do attached. Please ask any questions that'll help you understand better.

It's a late 2009 iMac.

 

[chrfr]

I have managed to erase the disk but when I tried to reinstall the OS, I got an error "Could not create a preboot volume for APFS". Based on what I read online, I unmounted the disk and and then tried to erase it and reformat it into Mac OS Extended (Journaled). Then I keep getting an error "Erase process has failed" I've got not idea where to go from here!!

Please help. Thanks

See screenshots of what I'm currently able to see/do attached. Please ask any questions that'll help you understand better.

It's a late 2009 iMac.

View attachment 802099 View attachment 802100 View attachment 802101 View attachment 802102 View attachment 802103 View attachment 802104

In Disk Utility, click on the container, and then click Unmount. You should then be able to erase the entire disk as HFS Extended (Journaled).

 

[davesmith123]

In Disk Utility, click on the container, and then click Unmount. You should then be able to erase the entire disk as HFS Extended (Journaled).

I don't see an unmount button. I've clicked everything else (even mount, which does nothing).

This is the error I get when I try to format the container 1 disk to Mac OS Extended

 

[chrfr]

I don't see an unmount button. I've clicked everything else (even mount, which does nothing).

This is the error I get when I try to format the container 1 disk to Mac OS ExtendedView attachment 802110

Oh, you're trying to erase the entire disk, which is where the Recovery partition is located, so you can't unmount that recovery partition. Since your computer doesn't support internet recovery, you'll need a USB boot drive to erase the entire disk.

 

[davesmith123]

Boot from internet recovery instead.

How do I do that? Thanks.

 

[chrfr]

How do I do that? Thanks.

I edited my post after you replied. Your computer doesn't support internet recovery, sorry about that. You'll need a USB drive, or if you have an older version of macOS on DVD, you can boot from that too.

 

[davesmith123]

OK, thanks. Gonna put together a USB boot disk and see what happens. Appreciate you taking the time to respond!