Required attribute "type" not found during EF migration

Question

The following error is thrown when running EF migrations against an Azure SQL database:

System.TypeInitializationException: The type initializer for 'System.Data.SqlClient.SqlConnection' threw an exception. ---> System.TypeInitializationException: The type initializer for 'System.Data.SqlClient.SqlConnectionFactory' threw an exception. ---> System.TypeInitializationException: The type initializer for 'System.Data.SqlClient.SqlPerformanceCounters' threw an exception. ---> System.Configuration.ConfigurationErrorsException: Required attribute 'type' not found. (--DATA OMITTED FOR PRIVACY REASONS--)
   at System.Configuration.BaseConfigurationRecord.EvaluateOne(String[] keys, SectionInput input, Boolean isTrusted, FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult)
   at System.Configuration.BaseConfigurationRecord.Evaluate(FactoryRecord factoryRecord, SectionRecord sectionRecord, Object parentResult, Boolean getLkg, Boolean getRuntimeObject, Object& result, Object& resultRuntimeObject)
   at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)
   at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)
   at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)
   at System.Configuration.BaseConfigurationRecord.GetSection(String configKey)
   at System.Configuration.ClientConfigurationSystem.System.Configuration.Internal.IInternalConfigSystem.GetSection(String sectionName)
   at System.Configuration.ConfigurationManager.GetSection(String sectionName)
   at System.Configuration.PrivilegedConfigurationManager.GetSection(String sectionName)
   at System.Diagnostics.DiagnosticsConfiguration.GetConfigSection()
   at System.Diagnostics.DiagnosticsConfiguration.Initialize()
   at System.Diagnostics.DiagnosticsConfiguration.get_SwitchSettings()
   at System.Diagnostics.Switch.InitializeConfigSettings()
   at System.Diagnostics.Switch.InitializeWithStatus()
   at System.Diagnostics.Switch.get_SwitchSetting()
   at System.Diagnostics.TraceSwitch.get_Level()
   at System.Data.ProviderBase.DbConnectionPoolCounters..ctor(String categoryName, String categoryHelp)
   at System.Data.SqlClient.SqlPerformanceCounters..ctor()
   at System.Data.SqlClient.SqlPerformanceCounters..cctor()
   --- End of inner exception stack trace ---
   at System.Data.SqlClient.SqlConnectionFactory..cctor()
   --- End of inner exception stack trace ---
   at System.Data.SqlClient.SqlConnection..cctor()
   --- End of inner exception stack trace ---
   at System.Data.SqlClient.SqlConnection..ctor()
   at System.Data.SqlClient.SqlClientFactory.CreateConnection()
   at System.Data.Entity.Internal.LazyInternalConnection.CreateConnectionFromProviderName(String providerInvariantName)
   at System.Data.Entity.Internal.LazyInternalConnection.InitializeFromConnectionStringSetting(ConnectionStringSettings appConfigConnection)
   at System.Data.Entity.Internal.LazyInternalConnection.Initialize()
   at System.Data.Entity.Internal.LazyInternalConnection.get_Connection()
   at System.Data.Entity.Internal.LazyInternalContext.get_Connection()
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbProviderInfo modelProviderInfo, AppConfig config, DbConnectionInfo connectionInfo)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Migrations.Design.MigrationScaffolder..ctor(DbMigrationsConfiguration migrationsConfiguration)
   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.SqlClient.SqlConnection' threw an exception.

The error started occurring after I enabled tracing for my application. Although I have solved this issue, I am posting it here in Q&A format in case anyone else comes across this problem.

Answer 1

In my case the problem came from

<system.diagnostics>
        <trace>
            <listeners>
                <add type="Microsoft.WindowsAzure.Diagnostics.DiagnosticMonitorTraceListener, Microsoft.WindowsAzure.Diagnostics, Version=2.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
                   name="AzureDiagnostics">
                    <filter type="" />
                </add>
            </listeners>
        </trace>
    </system.diagnostics>

when I deleted the type="" declaration because VS 2013 U4 says that "The 'type' attribute is not allowed". When reversed the deletion of the config declaration to the above it started to work again.

And it does not matter which version of Diagnostics you have. (Until 2.5.0.0 at least).

Answer 2

The problem was caused by our our tracing eventlistener. Simply comment out the Systems.Diagnostics tag in your web.config/app.config file when running your migrations.

Please +1 this answer if it helped you.