Force update of local path package.json dependency with npm

I'm using the local path feature of npm and package.json to develop (in Windows...) with a live version of a private package on my local drive, e.g.

"dependencies": {
  "foo": "file:..\\foo"
}

An npm install correctly goes to the directory and installs the latest code. But when I update code in ..\foo, an npm update (--force) or npm install does not pick up changes.

Is there any way to update local path packages (without having the delete the ...\node_modules\foo directory and re-npm install)?