At least 3 times in the past month I've tried to deploy something to vercel and ran into this error.

My project uses pnpm@9 and vercel is trying to install dependencies with pnpm@6, which is breaking and showing this in the build logs:

ERR_PNPM_UNSUPPORTED_ENGINE Unsupported environment (bad pnpm and/or Node.js version)

The underlying issue was that I had an old package-lock.json file from when I scaffolded the project with the NextJS CLI.

Deleting that package-lock file triggers a new deploy that works.

Hope this helps anyone running into this.

If you need a blog check out zenblog.com

Jordi.