Multiple npm install fails (EPERM error) - windows

Question

Im trying to install multiple packages in different child processes. And all the packages have some common dependency(browserify in my case).
example
|
|_pkg1
| |_browserify
|
|_pkg2
| |_browserify
|
|_pkg3
| |_browserify
|
|_run.js
run.js:
var packages = ['pkg1', 'pkg2', 'pkg3'];
packages.forEach(function(pkg){
exec('npm install ./' + pkg);
});
And node run.js fails with log
npm ERR! Windows_NT 6.3.9600
npm ERR! argv "c:\\Program Files\\nodejs\\\\node.exe" "c:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "i
nstall" "./pkg3"
npm ERR! node v0.12.2
npm ERR! npm v2.7.4
npm ERR! path C:\Users\Artem\AppData\Roaming\npm-cache\acorn\0.9.0\package\package.json
npm ERR! code EPERM
npm ERR! errno -4048
npm ERR! Error: EPERM, rename 'C:\Users\Artem\AppData\Roaming\npm-cache\acorn\0.9.0\package\package.json'
npm ERR! at Error (native)
npm ERR! { [Error: EPERM, rename 'C:\Users\Artem\AppData\Roaming\npm-cache\acorn\0.9.0\package\package.json']
npm ERR! errno: -4048,
npm ERR! code: 'EPERM',
npm ERR! path: 'C:\\Users\\Artem\\AppData\\Roaming\\npm-cache\\acorn\\0.9.0\\package\\package.json',
npm ERR! parent: 'syntax-error' }
npm ERR!
npm ERR! Please try running this command again as root/Administrator.
Example: https://github.com/SakerONE/multiple-npm-install

Answer 1

Works fine with npm 2.9.1
Just try to upgrade your npm
npm install npm#latest -g

Answer 2

This seems to be a tricky bug in npm, most probably, a race condition of parallel tasks writing the same package.json.
You can use --force flag to avoid cache (but it might be slow to download all dependencies on each build). Or wait for npm team to implement a permanent fix.
Related links to watch on Github:
https://github.com/Microsoft/vso-agent-tasks/issues/323
https://github.com/npm/npm/issues/2500
https://github.com/npm/npm/issues/9696