diff --git a/src/Features/Core/Portable/Diagnostics/Analyzers/PreferFrameworkTypeDiagnosticAnalyzerBase.cs b/src/Features/Core/Portable/Diagnostics/Analyzers/PreferFrameworkTypeDiagnosticAnalyzerBase.cs
index 5a9c814e92997e6559cbaf9f9db578f695eee058..5f4f74c7441c66bcf9578c8654ecfb173ee8c0f2 100644
--- a/src/Features/Core/Portable/Diagnostics/Analyzers/PreferFrameworkTypeDiagnosticAnalyzerBase.cs
+++ b/src/Features/Core/Portable/Diagnostics/Analyzers/PreferFrameworkTypeDiagnosticAnalyzerBase.cs
@@ -72,6 +72,7 @@ public sealed override void Initialize(AnalysisContext context)
         {
             context.RegisterSyntaxNodeAction(AnalyzeNode, SyntaxKindsOfInterest);
             context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.EnableConcurrentExecution();
         }
 
         protected void AnalyzeNode(SyntaxNodeAnalysisContext context)
diff --git a/src/Features/Core/Portable/Diagnostics/Analyzers/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs b/src/Features/Core/Portable/Diagnostics/Analyzers/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs
index 6ec1fd39f34b6c59fe6bed6961c65377f0161c40..1669925a3cd7db040f64e45f55a759e362dce781 100644
--- a/src/Features/Core/Portable/Diagnostics/Analyzers/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs
+++ b/src/Features/Core/Portable/Diagnostics/Analyzers/RemoveUnnecessaryCastDiagnosticAnalyzerBase.cs
@@ -29,6 +29,8 @@ internal abstract class RemoveUnnecessaryCastDiagnosticAnalyzerBase<TLanguageKin
         public sealed override void Initialize(AnalysisContext context)
         {
             context.ConfigureGeneratedCodeAnalysis(GeneratedCodeAnalysisFlags.None);
+            context.EnableConcurrentExecution();
+
             context.RegisterSyntaxNodeAction(
                 nodeContext =>
                     {
diff --git a/src/Features/Core/Portable/Diagnostics/Analyzers/UnboundIdentifiersDiagnosticAnalyzerBase.cs b/src/Features/Core/Portable/Diagnostics/Analyzers/UnboundIdentifiersDiagnosticAnalyzerBase.cs
index 470edee6082d6ceb3a1fa74c81937958b39bb53b..995fa0b3ab0d0f92f409cbf8ac097172e0ed5515 100644
--- a/src/Features/Core/Portable/Diagnostics/Analyzers/UnboundIdentifiersDiagnosticAnalyzerBase.cs
+++ b/src/Features/Core/Portable/Diagnostics/Analyzers/UnboundIdentifiersDiagnosticAnalyzerBase.cs
@@ -24,6 +24,8 @@ internal abstract class UnboundIdentifiersDiagnosticAnalyzerBase<TLanguageKindEn
 
         public override void Initialize(AnalysisContext context)
         {
+            context.EnableConcurrentExecution();
+
             context.RegisterSyntaxNodeAction(AnalyzeNode, this.SyntaxKindsOfInterest.ToArray());
         }
 
diff --git a/src/Features/Core/Portable/RemoveUnnecessaryImports/AbstractRemoveUnnecessaryImportsDiagnosticAnalyzer.cs b/src/Features/Core/Portable/RemoveUnnecessaryImports/AbstractRemoveUnnecessaryImportsDiagnosticAnalyzer.cs
index e4653ec3261eb2c4eddadc8e2525abcfffd50c59..b4ef591df428e3c77c514cf9bfa7e0799bd5a728 100644
--- a/src/Features/Core/Portable/RemoveUnnecessaryImports/AbstractRemoveUnnecessaryImportsDiagnosticAnalyzer.cs
+++ b/src/Features/Core/Portable/RemoveUnnecessaryImports/AbstractRemoveUnnecessaryImportsDiagnosticAnalyzer.cs
@@ -72,6 +72,8 @@ public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics
 
         public override void Initialize(AnalysisContext context)
         {
+            context.EnableConcurrentExecution();
+
             context.RegisterSemanticModelAction(this.AnalyzeSemanticModel);
         }
 
diff --git a/src/Features/Core/Portable/ValidateFormatString/AbstractValidateFormatStringDiagnosticAnalyzer.cs b/src/Features/Core/Portable/ValidateFormatString/AbstractValidateFormatStringDiagnosticAnalyzer.cs
index e7b00e91eebb61f6416f31b6789742e46dbc1bdd..e50be3a2b99349cde8bffcf56b9321f7683f8199 100644
--- a/src/Features/Core/Portable/ValidateFormatString/AbstractValidateFormatStringDiagnosticAnalyzer.cs
+++ b/src/Features/Core/Portable/ValidateFormatString/AbstractValidateFormatStringDiagnosticAnalyzer.cs
@@ -63,6 +63,8 @@ public override ImmutableArray<DiagnosticDescriptor> SupportedDiagnostics
 
         public override void Initialize(AnalysisContext context)
         {
+            context.EnableConcurrentExecution();
+
             context.RegisterCompilationStartAction(startContext =>
             {
                 var formatProviderType = startContext.Compilation.GetTypeByMetadataName(typeof(System.IFormatProvider).FullName);