MacBook Pro boots to question mark after login

Jim_ON wrote:

After installing the latest software update (10.15.7) on my 2017 MacBook Pro, it restarted showing a flashing question mark folder icon. After restarting again it gets to the login screen, then after login goes back to the question mark.

I re-booted in recovery mode, but the SSD isn't showing up in disk utility or OSX reinstall, or in terminal.

But when I start up to Startup Manager, I see two drives: 'macOS Installer' and 'Macintosh HD'

Also something strange happens when I shut down the computer (with either the menu items or power button). When I close the lid and open it again, without touching the power button, it shows the login screen, as if it never shut down.

I'm very confused. If the drive was busted, surly it shouldn't boot up at all? But if it was OSX that's corrupted, the drive should be available in recovery mode to reinstall the OS.

Can anyone help?

Is there anything else I can try?

Thanks.

—J.

If your Mac starts up to a question mark

https://support.apple.com/en-us/HT204323

on line Apple Support: https://getsupport.apple.com/

Call Customer Support (800) MY–APPLE (800–692–7753)

or call AppleCare Support at 1-800-APLCARE (800-275-2273)

If your Mac restarted unexpectedly, that indicates a kernel panic. You should read https://support.apple.com/en-us/HT200553.

Also, I see you're getting a flashing question mark folder upon restarting. If that happens on occasions, and your Mac starts up normally, it might need service repairs. Consider scheduling an appointment with a Genius at an Apple Store.