diff --git a/Barotrauma/BarotraumaShared/SharedSource/Screens/GameScreen.cs b/Barotrauma/BarotraumaShared/SharedSource/Screens/GameScreen.cs
index be3e4bb12..3dc8dfac2 100644
--- a/Barotrauma/BarotraumaShared/SharedSource/Screens/GameScreen.cs
+++ b/Barotrauma/BarotraumaShared/SharedSource/Screens/GameScreen.cs
@@ -25,7 +25,7 @@ namespace Barotrauma
 
         private static readonly ParallelOptions parallelOptions = new ParallelOptions
         {
-            MaxDegreeOfParallelism = Math.Max(4,Environment.ProcessorCount - 1),
+            MaxDegreeOfParallelism = Math.Max(1,Environment.ProcessorCount - 1),
         };
 
 #if CLIENT
diff --git a/Libraries/Farseer Physics Engine 3.5/Collision/DynamicTree.cs b/Libraries/Farseer Physics Engine 3.5/Collision/DynamicTree.cs
index 6bc690f09..9753764d6 100644
--- a/Libraries/Farseer Physics Engine 3.5/Collision/DynamicTree.cs	
+++ b/Libraries/Farseer Physics Engine 3.5/Collision/DynamicTree.cs	
@@ -1145,4 +1145,4 @@ namespace FarseerPhysics.Collision
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Libraries/Farseer Physics Engine 3.5/Dynamics/ContactManager.cs b/Libraries/Farseer Physics Engine 3.5/Dynamics/ContactManager.cs
index 1c47b8c05..8c7d9bd9e 100644
--- a/Libraries/Farseer Physics Engine 3.5/Dynamics/ContactManager.cs	
+++ b/Libraries/Farseer Physics Engine 3.5/Dynamics/ContactManager.cs	
@@ -27,9 +27,10 @@
 * 3. This notice may not be removed or altered from any source distribution. 
 */
 
-using System.Collections.Generic;
 using FarseerPhysics.Collision;
 using FarseerPhysics.Dynamics.Contacts;
+using System.Collections.Generic;
+using System.Threading;
 
 namespace FarseerPhysics.Dynamics
 {
@@ -61,6 +62,8 @@ namespace FarseerPhysics.Dynamics
         public int CollideMultithreadThreshold = 64;
         #endregion
 
+        // This will ensure only one thread will work on ContactList so that we wont mess up these stuff
+        private readonly SemaphoreSlim contactManagerSignal = new SemaphoreSlim(1);
 
         /// <summary>
         /// Fires when a contact is created
@@ -249,6 +252,8 @@ namespace FarseerPhysics.Dynamics
 
         internal void Destroy(Contact contact)
         {
+            contactManagerSignal.Wait(100);
+
             Fixture fixtureA = contact.FixtureA;
             Fixture fixtureB = contact.FixtureB;
             Body bodyA = fixtureA.Body;
@@ -310,6 +315,8 @@ namespace FarseerPhysics.Dynamics
             // Insert into the pool.
             contact.Next = _contactPoolList.Next;
             _contactPoolList.Next = contact;
+
+            contactManagerSignal.Release();
         }
 
         internal void Collide()
@@ -610,4 +617,4 @@ namespace FarseerPhysics.Dynamics
         }
 #endif
     }
-}
\ No newline at end of file
+}
diff --git a/Libraries/Farseer Physics Engine 3.5/Dynamics/Contacts/Contact.cs b/Libraries/Farseer Physics Engine 3.5/Dynamics/Contacts/Contact.cs
index c79e46edd..6e2eaaaa0 100644
--- a/Libraries/Farseer Physics Engine 3.5/Dynamics/Contacts/Contact.cs	
+++ b/Libraries/Farseer Physics Engine 3.5/Dynamics/Contacts/Contact.cs	
@@ -1,4 +1,4 @@
-// Copyright (c) 2017 Kastellanos Nikolaos
+// Copyright (c) 2017 Kastellanos Nikolaos
 
 /* Original source Farseer Physics Engine:
  * Copyright (c) 2014 Ian Qvist, http://farseerphysics.codeplex.com
@@ -496,4 +496,4 @@ namespace FarseerPhysics.Dynamics.Contacts
 
         #endregion
     }
-}
\ No newline at end of file
+}
diff --git a/Libraries/Farseer Physics Engine 3.5/Dynamics/World.cs b/Libraries/Farseer Physics Engine 3.5/Dynamics/World.cs
index 0aa2ef49a..f64765ad9 100644
--- a/Libraries/Farseer Physics Engine 3.5/Dynamics/World.cs	
+++ b/Libraries/Farseer Physics Engine 3.5/Dynamics/World.cs	
@@ -1726,4 +1726,4 @@ namespace FarseerPhysics.Dynamics
 
         }
     }
-}
\ No newline at end of file
+}