I\'m currently using Web Essentials 2013 update 4 to provide support for compiling .scss files in Visual Studio.
The tool has worked fine for me in the past however
I had a similar issue and turn out to be a reference to a SASS variable before it was declared. There were no warnings or errors. Once I move the reference to the right place it all worked fine.
Going off of what others have said about Web Essentials. Looking at the change log, it states that for versions 2013 update 4 and up (meaning version 2015 as well),
Important! Bundling, minification and compilation of LESS, Sass and CoffeeScript is not longer part of Web Essentials 2015. Install the new extensions Bundler & Minifier and Web Compiler instead. Also, see this list of other web development extensions that might be of interest to you.
I found this neat little extension for visual studio, that compiles the SCSS file(s) on save into a CSS file (along with minification for that file).
You can get it here. The guy that created this extension also talks about the Web Essential issue as well, found here.
Referencing the changelog, as of 2.5 for update 4 of Web Essentials:
- Removed all node.js based tools ◦Sass/LESS compilers JSHint/JSCS
linters CSS AutoPrefixer Handlebars compiler SweetJS/LiveScript
compilers
http://vswebessentials.com/changelog
So my understanding is, that it no longer compiles.