Scaffold-DbContext (EF Core Tools) throws 'Instance failure' exception

Question

Context

Currently I am creating an Extract, Transform and Load (ETL) application written in C# with .NET Core. The target of the ETL application is a database that is accessed through Entity Framework Core 2.1.0 and later 2.1.1. A database first approach is used, since the schema's are fixed. Microsoft offers the following guide to approach this situation. The guide states that the CLI command Scaffold-DbContext in the Package Manager Console can be used to generate the DbContext and the corresponding entity models.

Earlier in this project I have successfully used this CLI command. However the naming of the models did not correspond directly to the table and column names. The newer versions of this CLI Tooling offers a option -UseDatabaseNames, so I therefore opted to rerun this command in order to generate some updated models. Additionally, regenerating the DbContext is something I am planning to do more often in the future.

The Problem

Unfortunately running the Scaffold-DbContext command now returns the following error: Instance failure.. The verbose option gives some more insight into what is going wrong, but I am unclear as to what exactly is going wrong and how to resolve it.

Command

Scaffold-DbContext "[ConnectionString]" Microsoft.EntityFrameworkCore.SqlServer -UseDatabaseNames -OutputDir Models -v -force 

Verbose Output

Using project '[ProjectName]'. Using startup project '[ProjectName]'. Build started... Build succeeded. C:\Program Files\dotnet\dotnet.exe exec --depsfile C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\bin\Debug\netcoreapp2.1\[ProjectName].Service.deps.json --additionalprobingpath C:\Users\[MyComputerUsername]\.nuget\packages --additionalprobingpath "C:\Program Files\dotnet\sdk\NuGetFallbackFolder" --runtimeconfig C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\bin\Debug\netcoreapp2.1\[ProjectName].Service.runtimeconfig.json C:\Users\[MyComputerUsername]\.nuget\packages\microsoft.entityframeworkcore.tools\2.1.1\tools\netcoreapp2.0\any\ef.dll dbcontext scaffold Server=[ConnectionString] Microsoft.EntityFrameworkCore.SqlServer --json --output-dir Models --use-database-names --force --verbose --no-color --prefix-output --assembly C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\bin\Debug\netcoreapp2.1\[ProjectName].Service.dll --startup-assembly C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\bin\Debug\netcoreapp2.1\[ProjectName].Service.dll --project-dir C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\ --language C# --working-dir C:\Repos\[Client]\[ProjectName]\[ProjectName] --root-namespace [ProjectName].Service Using assembly '[ProjectName]'. Using startup assembly '[ProjectName]'. Using application base 'C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\bin\Debug\netcoreapp2.1'. Using working directory 'C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service'. Using root namespace '[ProjectName]'. Using project directory 'C:\Repos\[Client]\[ProjectName]\[ProjectName]\[ProjectName].Service\'. The EF Core tools version '2.1.1-rtm-30846' is older than that of the runtime '2.1.2-rtm-30932'. Update the tools for the latest features and bug fixes. Finding design-time services for provider 'Microsoft.EntityFrameworkCore.SqlServer'... Using design-time services from provider 'Microsoft.EntityFrameworkCore.SqlServer'. Finding design-time services referenced by assembly '[ProjectName]'. No referenced design-time services were found. Finding IDesignTimeServices implementations in assembly '[ProjectName]'... No design-time services were found. 

Exception

System.InvalidOperationException: Instance failure.    at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover)    at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)    at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)    at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)    at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling)    at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)    at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)    at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)    at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)    at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)    at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)    at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)    at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)    at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)    at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)    at System.Data.SqlClient.SqlConnection.Open()    at Microsoft.EntityFrameworkCore.SqlServer.Scaffolding.Internal.SqlServerDatabaseModelFactory.Create(DbConnection connection, IEnumerable`1 tables, IEnumerable`1 schemas)    at Microsoft.EntityFrameworkCore.SqlServer.Scaffolding.Internal.SqlServerDatabaseModelFactory.Create(String connectionString, IEnumerable`1 tables, IEnumerable`1 schemas)    at Microsoft.EntityFrameworkCore.Scaffolding.Internal.ReverseEngineerScaffolder.ScaffoldModel(String connectionString, IEnumerable`1 tables, IEnumerable`1 schemas, String namespace, String language, String contextDir, String contextName, ModelReverseEngineerOptions modelOptions, ModelCodeGenerationOptions codeOptions)    at Microsoft.EntityFrameworkCore.Design.Internal.DatabaseOperations.ScaffoldContext(String provider, String connectionString, String outputDir, String outputContextDir, String dbContextClassName, IEnumerable`1 schemas, IEnumerable`1 tables, Boolean useDataAnnotations, Boolean overwriteFiles, Boolean useDatabaseNames)    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.ScaffoldContextImpl(String provider, String connectionString, String outputDir, String outputDbContextDir, String dbContextClassName, IEnumerable`1 schemaFilters, IEnumerable`1 tableFilters, Boolean useDataAnnotations, Boolean overwriteFiles, Boolean useDatabaseNames)    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.ScaffoldContext.<>c__DisplayClass0_1.<.ctor>b__0()    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()    at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action) Instance failure. 

As stated before I am unclear what exactly is going wrong. My google searches have not resulted in any relevant information. Additionally I have tried updating the SDK, tools and other references. And I tried deleting the DbContext and models. Any help would be greatly appreciated!

Answer 1

I think you need to change your instance name.

For example :

Scaffold-DbContext "Server=PC\SQLEXPRESS;Database=***;User ID=sa;Password=****" Microsoft.EntityFrameworkCore.SqlServer -OutputDir model

So your instance in this case is : PC\\SQLEXPRESS. This instance should be like this : .\SQLEXPRESS

Answer 2

This is indeed an instance error. I copied the connection string from one of my classes. My SQL server instance is PC\Expresss, but my connection string was PC\\Express, just removed a back slash.