If your npm install fails on Vagrant / Windows, you should check:
- Can you create symlinks in the shared folder;
- Does the huge node_modules nested folder tree exceed the 260 character limit on Windows.
In our case, we ran into both issues at once. What finally solved the problem was:
- Moving the vagrant shared folder from something like C:/Users/username/projects/shared/[etc] simply to C:/shared
- Running sudo npm install –no-bin-links which tells npm not to create symlinks.