@tosti007 Well, it’s the

npm install 

that failed. But updating npm solved the issue since I had npm version 2.x.x (I think, not sure since I did not save the command prompt before the update). From the grunt dev page, higher npm version only raises warning for lower version number requirements and does nothing for

"grunt" : ">=version_number"

Which is good.

Forgot to report that the solution there worked when I tested https://forum.magicmirror.builders/topic/971/dependency-problems/6

Thank you for responding promptly to my post !

npm install npm -g
npm update -g

install me npm version 4.1.2 which now only raises a warning for yamllint (since that package.json asked exactly for 0.4.0).
Probably because of this : http://gruntjs.com/blog/2016-04-04-grunt-1.0.0-released#peer-dependencies

No guarantee, but I think I have npm version 2 something before, which hard error on that issue.

@teandryk @arosenhave Hello, I have run into the same issue wanting to install the magic mirror² framework on my windows laptop to develop a module. Running sudo node install.js from my powershell or from a node.js prompt did nothing to solve my problem. As far as I gathered, the issue come from this 2 not-updated packages that MagicMiror is using : https://github.com/geedew/grunt-yamllint/blob/master/package.json and the one called grunt-eslint. Both did not update their package.json (and maybe code) as the grunt developpers asked : http://gruntjs.com/blog/2016-04-04-grunt-1.0.0-released#peer-dependencies . Here is a topic on a forum surrounding that updating issue. However I am uncertain about what to do right now to solve it since the raspeberry pi environment and a laptop are not similar.