2021 MBP not starting after updating from 13.6 to 13.6.1

ScottVO wrote:

I attempted to make the same update on my 2021 16" MBP (16GB RAM, 1TB drive

using a good wifi connection to the same network. After 5 hours of leaving it alone, the MBP won't start.

When I briefly press the fingerprint/power button nothing happens. When I press and hold that button the power cord light flashes orange briefly, then goes back to green. Nothing happens. I repeat the 'press and hold' process a second time and the MBP restarts for a moment, displaying the white apple startup screen and the startup sound. Then it goes dark and remains unresponsive.

I updated using a fast wifi connection (Googlefiber). The power plug was attached since the process began. There is plenty of room on the hard drive. The MBP worked fine before the update process.

Is the update process simply taking a lot longer than it did on the Mac Studio Pro? Any suggestions? I'm prepared to leave it overnight to see if that works, before I schedule a service call using my AppleCare.

If the drive is failing this would be a hardware issue....

If your Mac starts up to a blank screen (white, black, gray, or blue)

If your Mac starts up to a blank screen - Apple Support

You can try the Configurator to revive or restore in an effort to resuscitate the problem mac

Revive or restore a Mac with Apple silicon using Apple Configurator - Apple Support

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"

Genius Bar Reservation and Apple Support Options - Apple

Outside the USA

Contact Apple for support and service - Apple Support

Check your coverage

My Support - Official Apple Support