Google Chrome "Failed parsing SourceMap" : css.map (Web Essential)
Problem is that WebEssentials saves files in UTF8 with BOM, but Chrome is not able to open these files as .map files.
As a temporary fix, you can go to your .map file in Visual Studio and save it as a Unicode (UTF-8 without signature) or US-ASCII using
File -> Advanced Save Options -> Unicode (UTF-8 without signature) or US-ASCII.It is possible that on changing the associated .css file you will have to repeat this process. However, when I tested adding some rules to .css the correct format was preserved for the .map file.
I reported this on WebEssentials GitHub:Issue 1993
And there are some other reports: