Could not load file or assembly 'WebGrease, Version=1.5.1.25624, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies

Question

I have an MVC4 Web API project. While running the service project I am getting an error

Could not load file or assembly \'WebGrease, Version=1.5.1.25624,

Answer 1

I know it's kind of late for the OP but I ran into the same problem while trying out the Bootstrap 3 for MVC 4 NuGet package, in my case it had something to do with the Microsoft.AspNet.Web.Optimization package, and managed to find a simple solution.

Try executing the following commands in the package manager console:

Install-Package Microsoft.AspNet.Web.Optimization
Update-Package WebGrease
Uninstall-Package Microsoft.AspNet.Web.Optimization
Uninstall-Package WebGrease
Install-Package Microsoft.AspNet.Web.Optimization
Update-Package WebGrease

The first two lines had no effect for me since those packages were already installed and updated by the Bootstrap 3 for MVC 4 package, but I ran them anyway and then it all compiled and ran great.