Attempting Monterey Clean Install on early 2015 MBP

[csonni]

So from what I can gather, Clean Installs (as we knew it) is no longer an option for certain Macs (such as mine). I had created a bootable Monterey Install flash drive and booted into it but now it's giving me a MacOS Recovery mode. When I click Erase Mac, it says, "If you are unable to unlock this Mac, you can fully erase it and reinstall MacOS. This will delete all media, data and settings on all volumes on this Mac. An Internet connection will be required to reinstall MacOS."

I am wanting to Clean Install Monterey on my OEM Apple SSD before removing it and replacing it with an NVMe drive.

I'm a bit hesitant to go on at this point. It seems as though it thinks I forgot my user password and need to reinstall the OS. Not sure where to go from here. Is Clean Install no longer an option? What the next best thing? A recovery? Never done that before. I might want to hard wire to my router for that for the best speed, no? Any suggestions?

 

[csonni]

So, it looks like I need to boot into Recovery Mode in order to allow booting from there flash drive.

Once your Mac is in recovery mode, you can update your security settings to allow the machine to boot from a USB stick.

• For older Intel Macs without the T2 chip, click Utilities and select Startup Security Utility located at the top bar menu. Check if the option “Firmware Password Protection” is in the off state. If it is on, turn off password protection.

 

[csonni]

So, in Startup Security Utility, I see that Firmware Password Protection is already turned off. So, now on to installing MacOS.

 

[chabig]

There is no need to make this hard. Forget about booting from an external drive. Boot from recovery, erase the Mac partition,and install Monterey.

 

[csonni]

All went fine. Since I had the install flash drive, it probably went a bit quicker than it would in recovery mode having to download all that again.