"Already up-to-date" and "Run 'yarn' to install missing dependencies"?

It looks like you want to do yarn install --check-files to verify that the files have not been removed from node_modules. This avoids having to wipe out your node_modules file which can be time consuming.

https://classic.yarnpkg.com/en/docs/cli/install/#toc-yarn-install-check-files https://github.com/yarnpkg/yarn/issues/2240

When yarn gets confused like this, you can usually fix things up by clearing out your node modules before installing:

rm -rf node_modules && yarn