Same problem here, did you manage to solve it

To be more clear, this is not a Turborepo problem. It's an issue with Corepack.

@luketevl I managed to solve this in a Github Actions runner by adding a step to install and enable Corepack. I imagine this will work other places as well since the issue is directly related to Corepack.

npm i -g --force corepack && corepack enable

@anthonyshew I think it would be helpful if there were some additional messaging about this either in the CLI output or in the documentation as it's definitely not expected behavior.

This is only present in when packageManger is specified in package.json, which Turborepo now requires. Many of the temporary solutions I saw involved removing packageManager, which isn't really viable here.

For context, this happened to me after creating a new repo with npx create-turbo@latest and having a basic Github Action to run unit tests via npm. The project doesn't use yarn anywhere, and all of the error messages (both locally and in the Github Action runner) hint at yarn being the root of the issue.