I have an error when i add app i juste install

The installation of the main module of 2sxc is ok. When i want to add app, it give me advice to install 13 apps, i select all and install all of them. Then i can use and choose app. If i choose the FAQ app, i have a system.object error

Here is the complete error (from my french installation)

Error: System.Web.HttpCompileException (0x80004005): c:\inetpub\wwwroot\Portals\7\2sxc\FAQ with Categories_All questions (sorted) of a selected category.cshtml(22): error CS0012: Le type 'System.Object' est défini dans un assembly qui n'est pas référencé. Vous devez ajouter une référence à l'assembly 'System.Runtime, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. à System.Web.Compilation.AssemblyBuilder.Compile() à System.Web.Compilation.BuildProvidersCompiler.PerformBuild() à System.Web.Compilation.BuildManager.CompileWebFile(VirtualPath virtualPath) à System.Web.Compilation.BuildManager.GetVPathBuildResultInternal(VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate) à System.Web.Compilation.BuildManager.GetVPathBuildResultWithNoAssert(HttpContext context, VirtualPath virtualPath, Boolean noBuild, Boolean allowCrossApp, Boolean allowBuildInPrecompile, Boolean throwIfNotFound, Boolean ensureIsUpToDate) à System.Web.Compilation.BuildManager.GetVirtualPathObjectFactory(VirtualPath virtualPath, HttpContext context, Boolean allowCrossApp, Boolean throwIfNotFound) à System.Web.Compilation.BuildManager.GetCompiledType(VirtualPath virtualPath) à ToSic.SexyContent.Engines.RazorEngine.CreateWebPageInstance() dans C:\Projects\2sxc-dnn742\Website\DesktopModules\ToSIC_SexyContent\2Sexy Content Razor\RazorEngine.cs:ligne 109 à ToSic.SexyContent.Engines.RazorEngine.InitWebpage() dans C:\Projects\2sxc-dnn742\Website\DesktopModules\ToSIC_SexyContent\2Sexy Content Razor\RazorEngine.cs:ligne 126 à ToSic.SexyContent.Engines.RazorEngine.Init() dans C:\Projects\2sxc-dnn742\Website\DesktopModules\ToSIC_SexyContent\2Sexy Content Razor\RazorEngine.cs:ligne 30 à ToSic.SexyContent.Engines.EngineBase.Init(Template template, App app, IInstanceInfo hostingModule, IDataSource dataSource, InstancePurposes instancePurposes, SxcInstance sxcInstance, Log parentLog) dans C:\Projects\2sxc-dnn742\Website\DesktopModules\ToSIC_SexyContent\ToSic.Sxc\SexyContent\Engines\EngineBase.cs:ligne 62 à ToSic.SexyContent.SxcInstance.GetRenderingEngine(InstancePurposes renderingPurpose) dans C:\Projects\2sxc-dnn742\Website\DesktopModules\ToSIC_SexyContent\ToSic.Sxc\SexyContent\SxcInstance_Render.cs:ligne 121 à ToSic.SexyContent.SxcInstance.Render() dans C:\Projects\2sxc-dnn742\Website\DesktopModules\ToSIC_SexyContent\ToSic.Sxc\SexyContent\SxcInstance_Render.cs:ligne 29

welcome to stackoverflow :)

Could you provide more details? like versions etc.?

BTW: This may help you https://github.com/2sic/2sxc/issues/1595

this may also help: How to fix 'Could not load file or assembly 'System.Web.Helpers, Version=2.0.0.0' Error with 2sxc in DNN