There are various issues scattered around the repo related to this issue. Basically what happens is, for some packages, when you try to require some-module in a file, for example,

var someModule = require('some-module');

It is unable to resolve the package and the following error appears,

Unable to resolve module some-module from /Users/username/projectname/AwesomeProject/index.js: Invalid directory /Users/node_modules/some-module

This error message is a symptom of the packager not being able to find some-module. It'll walk up the directory tree until it finds node_modules/some-module. It just so happens that /Users is the last directory to try, hence the weird /Users/node_modules directory in the error message (h/t @philikon).

Workarounds

Currently, the workarounds seem to be,

• Delete the node_modules folder - rm -rf node_modules && npm install
• Reset packager cache - rm -fr $TMPDIR/react-* or node_modules/react-native/packager/packager.sh --reset-cache
• Clear watchman watches - watchman watch-del-all
• Recreate the project from scratch