diff --git a/Build/build.ps1 b/Build/build.ps1
index 636874bc..9f4273dc 100644
--- a/Build/build.ps1
+++ b/Build/build.ps1
@@ -8,7 +8,7 @@
   $signAssemblies = $false
   $signKeyPath = "C:\Development\Releases\newtonsoft.snk"
   $buildDocumentation = $false
-  $buildNuGet = $true
+  $buildNuGet = $false
   $treatWarningsAsErrors = $false
   $workingName = if ($workingName) {$workingName} else {"Working"}
   $netCliVersion = "1.0.0"
diff --git a/Src/Newtonsoft.Json.Tests/Serialization/JsonSerializerCollectionsTests.cs b/Src/Newtonsoft.Json.Tests/Serialization/JsonSerializerCollectionsTests.cs
index 6c54d628..178299fa 100644
--- a/Src/Newtonsoft.Json.Tests/Serialization/JsonSerializerCollectionsTests.cs
+++ b/Src/Newtonsoft.Json.Tests/Serialization/JsonSerializerCollectionsTests.cs
@@ -25,11 +25,9 @@
 
 using System;
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Collections.Specialized;
 using System.Runtime.Serialization;
-#if !(NET35 || NET20 || PORTABLE || PORTABLE40)
-using System.Collections.Concurrent;
-#endif
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Globalization;
@@ -63,6 +61,53 @@ namespace Newtonsoft.Json.Tests.Serialization
     [TestFixture]
     public class JsonSerializerCollectionsTests : TestFixtureBase
     {
+#if !(NET20 || NET35)
+        [Test]
+        public void SerializeConcurrentQueue()
+        {
+            ConcurrentQueue<int> queue1 = new ConcurrentQueue<int>();
+            queue1.Enqueue(1);
+
+            string output = JsonConvert.SerializeObject(queue1);
+            Assert.AreEqual(@"[1]", output);
+
+            ConcurrentQueue<int> queue2 = JsonConvert.DeserializeObject<ConcurrentQueue<int>>(output);
+            int i;
+            Assert.IsTrue(queue2.TryDequeue(out i));
+            Assert.AreEqual(1, i);
+        }
+
+        [Test]
+        public void SerializeConcurrentBag()
+        {
+            ConcurrentBag<int> bag1 = new ConcurrentBag<int>();
+            bag1.Add(1);
+
+            string output = JsonConvert.SerializeObject(bag1);
+            Assert.AreEqual(@"[1]", output);
+
+            ConcurrentBag<int> bag2 = JsonConvert.DeserializeObject<ConcurrentBag<int>>(output);
+            int i;
+            Assert.IsTrue(bag2.TryTake(out i));
+            Assert.AreEqual(1, i);
+        }
+
+        [Test]
+        public void SerializeConcurrentStack()
+        {
+            ConcurrentStack<int> stack1 = new ConcurrentStack<int>();
+            stack1.Push(1);
+
+            string output = JsonConvert.SerializeObject(stack1);
+            Assert.AreEqual(@"[1]", output);
+
+            ConcurrentStack<int> stack2 = JsonConvert.DeserializeObject<ConcurrentStack<int>>(output);
+            int i;
+            Assert.IsTrue(stack2.TryPop(out i));
+            Assert.AreEqual(1, i);
+        }
+#endif
+
         [Test]
         public void DoubleKey_WholeValue()
         {
diff --git a/Src/Newtonsoft.Json/Serialization/DefaultContractResolver.cs b/Src/Newtonsoft.Json/Serialization/DefaultContractResolver.cs
index 0fee0df3..d5e840f3 100644
--- a/Src/Newtonsoft.Json/Serialization/DefaultContractResolver.cs
+++ b/Src/Newtonsoft.Json/Serialization/DefaultContractResolver.cs
@@ -26,9 +26,6 @@
 using System;
 using System.Collections;
 using Newtonsoft.Json.Schema;
-#if HAVE_CONCURRENT_COLLECTIONS
-using System.Collections.Concurrent;
-#endif
 using System.Collections.Generic;
 using System.ComponentModel;
 #if HAVE_DYNAMIC
@@ -884,15 +881,33 @@ namespace Newtonsoft.Json.Serialization
             }
         }
 
+        private static bool IsConcurrentCollection(Type t)
+        {
+            if (t.IsGenericType())
+            {
+                Type definition = t.GetGenericTypeDefinition();
+
+                switch (definition.FullName)
+                {
+                    case "System.Collections.Concurrent.ConcurrentQueue`1":
+                    case "System.Collections.Concurrent.ConcurrentStack`1":
+                    case "System.Collections.Concurrent.ConcurrentBag`1":
+                    case "System.Collections.Concurrent.ConcurrentDictionary`2":
+                        return true;
+                }
+            }
+
+            return false;
+        }
+
         private static bool ShouldSkipDeserialized(Type t)
         {
-#if HAVE_CONCURRENT_COLLECTIONS
             // ConcurrentDictionary throws an error in its OnDeserialized so ignore - http://json.codeplex.com/discussions/257093
-            if (t.IsGenericType() && t.GetGenericTypeDefinition() == typeof(ConcurrentDictionary<,>))
+            if (IsConcurrentCollection(t))
             {
                 return true;
             }
-#endif
+
 #if HAVE_FSHARP_TYPES
             if (t.Name == FSharpUtils.FSharpSetTypeName || t.Name == FSharpUtils.FSharpMapTypeName)
             {
@@ -905,14 +920,13 @@ namespace Newtonsoft.Json.Serialization
 
         private static bool ShouldSkipSerializing(Type t)
         {
-#if HAVE_FSHARP_TYPES
-            if (t.Name == FSharpUtils.FSharpSetTypeName || t.Name == FSharpUtils.FSharpMapTypeName)
+            if (IsConcurrentCollection(t))
             {
                 return true;
             }
-#endif
-#if DOTNET
-            if (t.IsGenericType() && t.GetGenericTypeDefinition() == typeof(ConcurrentDictionary<,>))
+
+#if HAVE_FSHARP_TYPES
+            if (t.Name == FSharpUtils.FSharpSetTypeName || t.Name == FSharpUtils.FSharpMapTypeName)
             {
                 return true;
             }