Could not load type 'System.Web.Optimization.StyleBundle'
asp.net, asp.net-mvc
Solution
As per Roman Nikitin Comment:
I found issue myself. There was wrong reference to `System.Web.Optimization.dll`, my website tried to use old version. Deleting package and then re-adding helps not every time.
The solution is: fully delete old package, references and package configurations from all web-sites and then add it again.
Problem
Sometimes after build and launch my MVC4 web app I got this error. It can dissapear after rebuild or not. Same issue I got after publish to Windows Azure. Does anybody know how to fix this error? ``` Server Error in '/' Application. Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.TypeLoadException: Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [TypeLoadException: Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.] Inventarium.Web.Mobile.App.BundleConfig.RegisterBundles(BundleCollection bundles) in c:\dev\Inventarium\Inventarium.Web\Inventarium.Web.Mobile.App\App_Start\BundleConfig.cs:30 Inventarium.Web.Mobile.App.MvcApplication.Application_Start() in c:\dev\Inventarium\Inventarium.Web\Inventarium.Web.Mobile.App\Global.asax.cs:18 [HttpException (0x80004005): Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.] System.Web.HttpApplicationFactory.EnsureAppStartCalledForIntegratedMode(HttpContext context, HttpApplication app) +4058245 System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +191 System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +352 System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +407 System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +375 [HttpException (0x80004005): Could not load type 'System.Web.Optimization.StyleBundle' from assembly 'System.Web.Optimization, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'.] System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +11703488 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +141 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +4870277 ```