sunhwa48 wrote:
Initially my macbook pro was looping when to start. With command, it can enter windows 10 partitioned to macos. But it goes back the loop once I choose macos.
Then I tried to reinstall MacOS using recovery option, but it couldn't access any of MacOs.
So, I used bootable usb drive(Montray, same macOS in my macbook), which was purchased from amazon.
After inserting the usb drive, I tried to boot the Macbook. But the usb drive kept showing light on and off repeatedly. Even windows doesn't run anymore after I ejected the usb drive.
Now Macbook is totally on and off when to start without showing any apple logo.
Was Windows 10 installed using Bootcamp - the proper way to switch from Windows back macOS is to use the Option Key at a cold boot up and choose the macOS to startup from.
Purchasing a USB Installer from whom every is risky IMHO.
Who knows what is actually on the USB Drive.
There are those will may or may not add things with can be harmful to the Computer
You might be better serviced by making a Bootable Installer.
The Bootable Installer can Only be performed on an Apple Computer
This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Monterey would have to be done on a computer that Qualifies to run Monterey.
Notation: If the computer being used to perform this action is Too New or Too Old to qualify to run the version of macOS - this computer can not be used.
Alternative is, to gain access to a Qualifying Apple Computer from a family member, friend or associate.
Extra Special Notation regarding the Touch ID equipped Apple Computer.
About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting
