yarn error

Oracle:site chris$ yarn install
yarn install v0.16.1
[1/4] 🔍  Resolving packages...
[2/4] 🚚  Fetching packages...
[3/4] 🔗  Linking dependencies...
[4/4] 📃  Building fresh packages...
success Saved lockfile.
$ node -e "require('fs').symlinkSync(require('path').resolve('node_modules/@bower_components'), 'app/assets/com', 'junction')"
fs.js:110
    throw err;
    ^

Error: EEXIST: file already exists, symlink '/Users/chris/Documents/code/red_nucleus/dermira_360/site/node_modules/@bower_components' -> 'app/assets/com'
    at Object.fs.symlinkSync (fs.js:968:3)
    at [eval]:1:15
    at Script.runInThisContext (vm.js:91:20)
    at Object.runInThisContext (vm.js:298:38)
    at Object.<anonymous> ([eval]-wrapper:6:22)
    at Module._compile (internal/modules/cjs/loader.js:678:30)
    at evalScript (internal/bootstrap/node.js:542:27)
    at startup (internal/bootstrap/node.js:204:9)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:575:3)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
Oracle:site chris$