PROBLEM: Downgrading New Mac to Sequoia

Hi all,

I have followed the Mr Macintosh video on ‘how to downgrade from Tahoe to Sequoia in 5 minutes without data loss’. I am doing this on a new m2 MacBook Air, which arrived with Tahoe but I wish to downgrade to Sequoia. After it seemed sequoia had finished installing to the Macintosh HD, this message pops up. I can’t find anything useful online, I wonder if anyone can help?

As it is a new Mac there is no data to lose on it fortunately! Once this is sorted, I’ll transfer my data from an Intel Mac running Monterey :)