Failed to complete setup of assembly (FileLoadException) - asp.net

Question

I'm have a tough time getting to the bottom of this issue. My ASP.NET project had a Nuget package dependency on Newtonsoft.Json 10.0.3 as well as a project reference to a class library project in the same solution. The ASP.NET project also has the following binding redirect in the web.config file.
<dependentAssembly>
<assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
<bindingRedirect oldVersion="0.0.0.0-10.0.0.0" newVersion="10.0.0.0" />
</dependentAssembly>
The referenced class library project in the solution then took a new dependency on Newtonsoft.Json 6.0.8 and I started getting the error below when running the ASP.NET project.
Server Error in '/' Application.
Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
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.IO.FileLoadException: Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
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.
Assembly Load Trace: The following information can be helpful to determine why the assembly 'Newtonsoft.Json' could not be loaded.
=== Pre-bind state information ===
LOG: DisplayName = Newtonsoft.Json
(Partial)
WRN: Partial binding information was supplied for an assembly:
WRN: Assembly Name: Newtonsoft.Json | Domain ID: 2
WRN: A partial bind occurs when only part of the assembly display name is provided.
WRN: This might result in the binder loading an incorrect assembly.
WRN: It is recommended to provide a fully specified textual identity for the assembly,
WRN: that consists of the simple name, version, culture, and public key token.
WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue.
LOG: Appbase = file:///C:/Users/xxx/source/repos/xxx/xxx/
LOG: Initial PrivatePath = C:\Users\xxx\source\repos\xxx\xxx\bin
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Users\xxx\source\repos\xxx\xxx\web.config
LOG: Using host configuration file: C:\Users\xxx\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Users/xxx/AppData/Local/Temp/Temporary ASP.NET Files/vs/b435bcee/4d9f637b/Newtonsoft.Json.DLL.
LOG: Attempting download of new URL file:///C:/Users/xxx/AppData/Local/Temp/Temporary ASP.NET Files/vs/b435bcee/4d9f637b/Newtonsoft.Json/Newtonsoft.Json.DLL.
LOG: Attempting download of new URL file:///C:/Users/xxx/source/repos/xxx/xxx/bin/Newtonsoft.Json.DLL.
LOG: Using application configuration file: C:\Users\xxx\source\repos\xxx\xxx\web.config
LOG: Using host configuration file: C:\Users\xxx\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Redirect found in application configuration file: 6.0.0.0 redirected to 10.0.0.0.
LOG: Post-policy reference: Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed
LOG: Attempting download of new URL file:///C:/Users/xxx/AppData/Local/Temp/Temporary ASP.NET Files/vs/b435bcee/4d9f637b/Newtonsoft.Json.DLL.
LOG: Attempting download of new URL file:///C:/Users/xxx/AppData/Local/Temp/Temporary ASP.NET Files/vs/b435bcee/4d9f637b/Newtonsoft.Json/Newtonsoft.Json.DLL.
LOG: Attempting download of new URL file:///C:/Users/xxx/source/repos/xxx/xxx/bin/Newtonsoft.Json.DLL.
WRN: Comparing the assembly name resulted in the mismatch: Major Version
ERR: Failed to complete setup of assembly (hr = 0x80131040). Probing terminated.
Stack Trace:
[FileLoadException: Could not load file or assembly 'Newtonsoft.Json' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
[FileLoadException: Could not load file or assembly 'Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +0
System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +36
System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +152
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean forIntrospection) +77
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +21
System.Reflection.Assembly.Load(String assemblyString) +28
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +38
[ConfigurationErrorsException: Could not load file or assembly 'Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +738
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +217
System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +130
System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +170
System.Web.Compilation.BuildManager.GetPreStartInitMethodsFromReferencedAssemblies() +92
System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath, Boolean& isRefAssemblyLoaded) +290
System.Web.Compilation.BuildManager.ExecutePreAppStart() +157
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +549
[HttpException (0x80004005): Could not load file or assembly 'Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) [phone]
System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +95
System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +254
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.2623.0
Changing the binding redirect in the web.config file to the following fixes the issue.
<dependentAssembly>
<assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
<bindingRedirect oldVersion="0.0.0.0-10.0.0.0" newVersion="6.0.0.0" />
</dependentAssembly>
Forcing the runtime version to 6.0.0.0 does not seem ideal, however, as other projects in the solution depend on 10.0.3 as well. Note that updating the class library in question to 10.0.3 does not fix the issue either. Only changing the binding redirect.
Any ideas?

Answer 1

Why does the class library reference a different version of Newtonsoft than the asp.net project? Here is my advice: go to the package manager of the class library. Uninstall the Newtonsoft package. Search for the latest Newtonsoft package, download/install it. Alternatively, you can update the installed version of Newtonsoft in the class library.