Reimaging MBP SSD, erasing as root?

[robertcoogan]

I removed an installation of Ubuntu from my MBP and now I have a 1.06 GB partition that won't mount and won't let me recombine it with the main macOS partition. I had read (yes, on the Ubuntu forums) that I should boot from and install from a flash drive and use Disk Utility on the installer to wipe the SSD as root.

This seems like a really bad idea. But I am at a loss as to how to figure out how to reclaim this unmountable partition. I still would like to do a clean install, but that won't help me reclaim the partition (listed as "disk0s3" below).

Any suggestions?

 

[Taz Mangus]

Since you want to do a clean install try booting into Recovery Mode, start Disk Utility, select Apple SSD SM2048L Media and click on Erase followed by install of Catalina 10.15.6. I would think that should erase and remove disk0s3 partition. You can also create a bootable USB installer and boot from that to erase and install Catalina 10.15.6.

How to reinstall macOS - Apple Support

You can use macOS Recovery, your computer's built-in recovery system, to reinstall the Mac operating system. Reinstalling macOS doesn't remove your personal data.

support.apple.com

Create a bootable installer for macOS - Apple Support

You can use a USB flash drive or other secondary volume as a startup disk from which to install the Mac operating system. These steps are primarily for system administrators and other experienced users who are familiar with entering commands in Terminal.

support.apple.com