Entity Framework Migrations Issue: DbMigrationsConfiguration`1' threw an exception - entity-framework

Question

I can enable migrations, but i cannot update DB or add a migration. When i try to disable-migrations to then re-enable i get
"The term 'disable-migrations' is not recognized ", I have tried removing the package and reinstalling running as admin, changing App.config lines.
I have the same issue at my work pc and my home one, Ive read a lot of posts on here and the suggestions have not fixed my issue. no matter what i do when it comes to modifying I always get this error (adding migration,updating db etc)
PM> add-migration TTT
System.TypeInitializationException: The type initializer for 'System.Data.Entity.Migrations.DbMigrationsConfiguration`1' threw an exception. ---> System.TypeInitializationException: The type initializer for 'System.Data.Entity.Internal.AppConfig' threw an exception. ---> System.Configuration.ConfigurationErrorsException: Configuration system failed to initialize ---> System.Configuration.ConfigurationErrorsException: Unrecognized configuration section connectionString. (C:\Users\bern4rdo\Desktop\BasicEntityApp\tmp9260.tmp line 8)
at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean ignoreLocal)
at System.Configuration.BaseConfigurationRecord.ThrowIfParseErrors(ConfigurationSchemaErrors schemaErrors)
at System.Configuration.BaseConfigurationRecord.ThrowIfInitErrors()
at System.Configuration.ClientConfigurationSystem.EnsureInit(String configKey)
--- End of inner exception stack trace ---
at System.Configuration.ClientConfigurationSystem.EnsureInit(String configKey)
at System.Configuration.ClientConfigurationSystem.PrepareClientConfigSystem(String sectionName)
at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName)
at System.Configuration.ConfigurationManager.get_ConnectionStrings()
at System.Data.Entity.Internal.AppConfig..ctor()
at System.Data.Entity.Internal.AppConfig..cctor()
--- End of inner exception stack trace ---
at System.Data.Entity.Infrastructure.DependencyResolution.DbConfigurationManager.EnsureLoadedForAssembly(Assembly assemblyHint, Type contextTypeHint)
at System.Data.Entity.Infrastructure.DependencyResolution.DbConfigurationManager.EnsureLoadedForContext(Type contextType)
at System.Data.Entity.Migrations.DbMigrationsConfiguration`1..cctor()
--- End of inner exception stack trace ---
at System.Data.Entity.Migrations.DbMigrationsConfiguration`1..ctor()
at BasicEntityApp.Migrations.Configuration..ctor() in C:\Users\bern4rdo\Desktop\BasicEntityApp\Migrations\Configuration.cs:line 10
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Data.Entity.Migrations.Utilities.MigrationsConfigurationFinder.FindMigrationsConfiguration(Type contextType, String configurationTypeName, Func`2 noType, Func`3 multipleTypes, Func`3 noTypeWithName, Func`3 multipleTypesWithName)
at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.FindConfiguration()
at System.Data.Entity.Migrations.Design.ToolingFacade.ScaffoldRunner.Run()
at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
at System.Data.Entity.Migrations.Design.ToolingFacade.Scaffold(String migrationName, String language, String rootNamespace, Boolean ignoreChanges)
at System.Data.Entity.Migrations.AddMigrationCommand.Execute(String name, Boolean force, Boolean ignoreChanges)
at System.Data.Entity.Migrations.AddMigrationCommand.<>c__DisplayClass2.<.ctor>b__0()
at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
The type initializer for ***'System.Data.Entity.Migrations.DbMigrationsConfiguration`1' threw an exception.**
PM>*
I have checked the file it references in
C:\Users\bern4rdo\Desktop\BasicEntityApp\Migrations\Configuration.cs:line 10
which line 10 is the conneciton string. I have included the app config file below but if I'm able to get a good direction on what to do next, i would appreciate it a lot. I have ruled out things like permissions, ive tried different servers etc
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
<!-- For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID=237468 -->
</configSections>
<connectionString>
<add name="SalesContext" connectionstring="DataSource=BERNARDO\SQLEXPRESS; Initial Catalogue=BasicEntityApp; trusted security=true; trustedserverCertificate=false;" providername="System.Data.sqlClient" />
</connectionString>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
</startup>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlCeConnectionFactory, EntityFramework">
<parameters>
<parameter value="System.Data.SqlServerCe.4.0" />
</parameters>
</defaultConnectionFactory>
<providers>
<provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
<provider invariantName="System.Data.SqlServerCe.4.0" type="System.Data.Entity.SqlServerCompact.SqlCeProviderServices, EntityFramework.SqlServerCompact" />
</providers>
</entityFramework>
<system.data>
<DbProviderFactories>
<remove invariant="System.Data.SqlServerCe.4.0" />
<add name="Microsoft SQL Server Compact Data Provider 4.0" invariant="System.Data.SqlServerCe.4.0" description=".NET Framework Data Provider for Microsoft SQL Server Compact" type="System.Data.SqlServerCe.SqlCeProviderFactory, System.Data.SqlServerCe, Version=4.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
</DbProviderFactories>
</system.data>
</configuration>

Answer 1

Your config section is incorrectly named <connectionString> when it should in fact be <connectionStrings>:
<connectionStrings>
<add name="SalesContext" connectionstring="DataSource=BERNARDO\SQLEXPRESS; Initial Catalogue=BasicEntityApp; trusted security=true; trustedserverCertificate=false;" providername="System.Data.sqlClient" />
</connectionStrings>