Hi there and welcome
Can you attempt the following please
Shut down your Mac.Find Command (⌘), Option, P, and R on your keyboard.Turn on your Mac.Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.Hold these keys until the computer restarts and you hear the startup sound for a second time.Release the keys.
Tell me if you can then get the computer to complete loading.
ok, if you Power off the mac
Then start the Mac and hold down the Command and R keys at startup.
It also remains at the white screen correct?
ok, and if you hold SHIFT and power it on with SHIFT held, same thing correct?
Thanks, ***** ***** are not needed as we confirmed the issue
It is the internal Sata port on the mainboard that has faulted.
I am really sorry about this and you are going to have to return the Mac to have this replaced. It will be covered by the warranty if this has not expired, and the replacement will be done at no cost to you.
I am really sorry about this, and if you have problems, or would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service by clicking one of the stars at the top of the page, then submit, that would be greatly appreciated.
You do indeed!
Sorry it is not better news but at least you now know
Let me know if you need anything else and please remember the service rating via one of the stars at the top then submit.