Today the ASP.NET and Web Tools 2012.2 update was released. Go download it right now!
It contains a lot of new and updated Visual Studio tooling features including:
- First class LESS editor
- Knockout.js Intellisense
- Paste JSON as classes
- CoffeeScript editor
- Mustache/Handlebars/JsRender syntax highlighting
- Page Inspector
- Live CSS auto-sync as you type
Some of them are features that started their lives in Web Essentials 2012 and are now ported into an official release. Every time we move features from the experimental Web Essentials extension into the official product, we try to make the transition as smooth as possible.
However, this time we moved some substantial features that are mutually exclusive – they register the same MEF components and that leads to this rather ugly exception:
This exception occurs when Web Tools 2012.2 is installed and you haven’t updated Web Essentials to version 2.5. The solution is simply to update Web Essentials. Go do that now. If you don’t have Web Essentials installed at all, you won’t get this error because then there is no conflict.