Monterey Installer Is Unable To Select The Startup Disk on M1 Mac

How are you running the installer? From a USB external flash drive? Also, the latest Monterey is 12.2.1 not 12.0.1 which is old. I would recommend deleting /Applications/Install macOS Monterey and re-installing from the App Store and run it right from within the macOS 11.5.2 operating system.

HeadphoneJack wrote:

Monterey Installer Is Unable To Select The Startup Disk on M1 Mac

macOS Monterey install can not select startup disk

The macOS Monterey 12.0.1 installer is unable to select the startup disk (Macintosh HD) because it thinks it isn't the startup disk, however, it is. It gives the error:

"You must provide authorization for this volume by setting it as your startup disk. You can relaunch the installer after authorization has been provided."

I am currently running macOS 11.5.2 (M1) It appears the issue is that the installer isn't properly requesting authorization before access.

https://discussions.apple.com/content/attachment/3a2129f9-e3ef-4b5b-b4df-8c030c050867

The current stable release of Big Sur is macOS 11.6.4

I would start there, and then try your Monterey upgrade and compare your results

Keep your Mac up to date - Apple Support

https://support.apple.com/guide/mac-help/get-macos-updates-mchlpx1065/mac

Have see some user attempting the upGrade to Monterey with out dated existing version of macOS like Big Sur 11.5.2.

As suggest previously - update to current version of Big Sur 11.6.4

Once that is achieved, then download a Current version of Monterey 12.2.1 and attempt the upgrade