Step 1: Ensure Proper Connection
- Double-check that your USB SSD is securely connected to your M1 MacBook Pro.
Step 2: Create a Bootable Installer
- Use another Mac to create a bootable macOS installer on a separate USB drive. You can do this by downloading the macOS Installer from the App Store and using Terminal or Disk Utility to create the installer.
Step 3: Boot Into Startup Manager
- Power off your MacBook Pro.
- Turn it on and hold down the power button until you see "Loading options" in the upper-right corner of the screen. Release the power button at this point.
- This should take you to the Startup Manager where you can select the bootable USB drive containing the macOS installer.
Step 4: Access macOS Utilities
- After successfully booting from the USB drive, you should see the macOS Utilities window.
Step 5: Reinstall macOS
- Select "Reinstall macOS" to initiate the reinstallation process.
If your USB SSD is still not detected, try using a different USB port or cable to rule out any connection issues.
Important: Make sure your USB SSD is correctly formatted and that it meets the system requirements for macOS installation.
If you've tried all these steps and the issue persists, it's advisable to contact Apple Support or visit an authorized service provider for further assistance, as there may be underlying hardware or software issues that require professional attention.
