Error: File to import not found or unreadable: ~bootstrap/scss/bootstrap
When Sass is precompiled by its own CLI, it processes @imports by itself, and sometimes thus doesn’t understand ~ notation. So you can import "node_modules/bootstrap/scss/bootstrap"; in first place and replaced the ~ notation with node_modules/ instead.
I had a similar error
File to import not found or unreadable: node_modules/bootstrap-sass/assets/stylesheets/bootstrap
Just add "bootstrap-sass": "^3.3.7", to devDependencies at yours package.json, ad run npm update, npm install in your project directory.
For me, I had to change the way I was importing
@import '../../../node_modules/bootstrap/scss/bootstrap';Then it works