[FIXED] Why am I encountering an error when I run "Add-Migration InitialCreate" in .NET?

Issue

I have an app that I am building with Asp.net MVC and .NET core 3.1. I have created the model, database context class and controller. When I try to run the command in the package manager command line: Add-Migration InitialCreate I get the following error:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.TypeLoadException: Could not load type 'Microsoft.EntityFrameworkCore.Internal.SemanticVersionComparer' from assembly 'Microsoft.EntityFrameworkCore, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. at Microsoft.EntityFrameworkCore.Design.OperationExecutor..ctor(IOperationReportHandler reportHandler, IDictionary args) --- End of inner exception stack trace --- at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions) at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) at System.Activator.CreateInstance(Type type, Object[] args) at Microsoft.EntityFrameworkCore.Tools.ReflectionOperationExecutor..ctor(String assembly, String startupAssembly, String projectDir, String dataDirectory, String rootNamespace, String language) at Microsoft.EntityFrameworkCore.Tools.Commands.ProjectCommandBase.CreateExecutor() at Microsoft.EntityFrameworkCore.Tools.Commands.MigrationsAddCommand.Execute() at Microsoft.EntityFrameworkCore.Tools.Commands.CommandBase.<>c__DisplayClass0_0.b__0() at Microsoft.DotNet.Cli.CommandLine.CommandLineApplication.Execute(String[] args) at Microsoft.EntityFrameworkCore.Tools.Program.Main(String[] args) Exception has been thrown by the target of an invocation.

I've heard this might be to do with the Microsoft.EntityFrameworkCore.Design package, and that it needs to be updated to version 3.0.0. Just wondered which file this change needs to take place, and what the necessary code is that needs to be added.

Solution

Please use the v3.1.10 (or the latest 3.x available) for all the NuGet packages, as I stated in the comments. This is going to fix your issue

Answered By - Krusty

Answer Checked By - Dawn Plyler (PHPFixing Volunteer)