升级到ASP后打开现有项目的例外.NET MVC6 beta7

我正在使用Visual Studio 2015社区版并更新了我现有的ASP。NET MVC6应用程序到beta7。现在我不能再打开项目了。Visual Studio崩溃时出现以下异常:

08.09.2015 20:23:12
Crippling
System.AggregateException: One or more errors occurred. ---> Microsoft.Assumes+InternalErrorException: The specified default content type (Default) is not defined in the project item schema.
   at Microsoft.Assumes.Fail(String message, Boolean showAssert)
   at Microsoft.VisualStudio.ProjectSystem.Items.ProjectItemSchemaManagerBase.<ComputeCacheDataAsync>d__15.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.Items.ProjectItemSchemaManager.<CreateSchemaFromSnapshotDataAsync>d__21.MoveNext()
   --- End of inner exception stack trace ---
---> (Inner Exception #0) Microsoft.Assumes+InternalErrorException: The specified default content type (Default) is not defined in the project item schema.
   at Microsoft.Assumes.Fail(String message, Boolean showAssert)
   at Microsoft.VisualStudio.ProjectSystem.Items.ProjectItemSchemaManagerBase.<ComputeCacheDataAsync>d__15.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.VisualStudio.ProjectSystem.Items.ProjectItemSchemaManager.<CreateSchemaFromSnapshotDataAsync>d__21.MoveNext()<---

搜索错误消息指定的默认内容类型(default)未在项目项架构中定义。没有带来任何有用的提示。一开始我以为这和dnvm有关。这是我的dnvm list结果:

Active Version     Runtime Architecture OperatingSystem Alias
------ -------     ------- ------------ --------------- -----
       1.0.0-beta5 clr     x64          win
       1.0.0-beta5 clr     x86          win
       1.0.0-beta5 coreclr x64          win
       1.0.0-beta5 coreclr x86          win
       1.0.0-beta6 clr     x64          win
       1.0.0-beta6 clr     x86          win
       1.0.0-beta7 clr     x64          win
  *    1.0.0-beta7 clr     x86          win             default
       1.0.0-beta7 coreclr x64          win
       1.0.0-beta7 coreclr x86          win

我的全球。Json是这样的:

{
    "projects": [ "src", "test" ],
    "sdk": {
        "version": "1.0.0-beta7"
    }
}

删除sdk部分不会改变任何东西。

编辑:this is my project.json

{
    "webroot": "wwwroot",
    "version": "1.0.0-*",
    "dependencies": {
        "Microsoft.AspNet.Mvc": "6.0.0-*",
        "Microsoft.AspNet.Server.IIS": "1.0.0-*",
        "Microsoft.AspNet.Server.WebListener": "1.0.0-*",
        "Microsoft.AspNet.StaticFiles": "1.0.0-*",
        "Microsoft.AspNet.Diagnostics": "1.0.0-*",
        "Microsoft.Framework.Configuration.Json": "1.0.0-*",
        "Microsoft.AspNet.Authentication": "1.0.0-*"
    },
    "commands": {
        "web": "Microsoft.AspNet.Hosting --config hosting.ini"
    },
    "frameworks": {
        "dnx451": { },
        "dnxcore50": { }
    },
    "compilationOptions": {
        "allowUnsafe": true
    },
    "exclude": [
        "wwwroot",
        "node_modules",
        "bower_components"
    ],
    "publishExclude": [
        "node_modules",
        "bower_components",
        "**.xproj",
        "**.user",
        "**.vspscc"
    ]
}