Mac 27'' 2011 boot problem

[marisug]

Hi.

I have mac 27'' 2011, because of HDD error I change HDD with used SSD from one Windows PC. Problem is that now it start windows automaticly
I had try to made bootable usb from Windows PC or from mac M2 but every time when I plug in USB (probably bootable ) and hold command at start up. It only find one HDD that is already inside, and no USB.


Is there any other way that I can install macOS back to mac 27''

 

[Nguyen Duc Hieu]

Hi.

I have mac 27'' 2011, because of HDD error I change HDD with used SSD from one Windows PC. Problem is that now it start windows automaticly
I had try to made bootable usb from Windows PC or from mac M2 but every time when I plug in USB (probably bootable ) and hold command at start up. It only find one HDD that is already inside, and no USB.


Is there any other way that I can install macOS back to mac 27''

1. Take out the SSD and delete all partitions on it.
2. Tripple PRAM reset.
Ctrl+Cmd+P+R right after pushing power button until 3 chimes. (5~8mins)
Now the iMac will show a signal that there is no loadable OS (folder icon + question mark)
3. Do the Internet Recovery. (Command + R or something)

Worst case scenario: Your iMac has a firmware password and you forget it.
Now it can only boot from the internal SSD.

You can also install Mac OS High Sierra on another Mac (not the M2, of course) and physically move it over the iMac.