diff --git a/dotnet/extlibs/csfml-audio.dll b/dotnet/extlibs/csfml-audio.dll
index fc371fb7..2d99395e 100644
Binary files a/dotnet/extlibs/csfml-audio.dll and b/dotnet/extlibs/csfml-audio.dll differ
diff --git a/dotnet/extlibs/csfml-graphics.dll b/dotnet/extlibs/csfml-graphics.dll
index ea86d772..638fa254 100644
Binary files a/dotnet/extlibs/csfml-graphics.dll and b/dotnet/extlibs/csfml-graphics.dll differ
diff --git a/dotnet/extlibs/csfml-window.dll b/dotnet/extlibs/csfml-window.dll
index 32cd8a1e..baa48022 100644
Binary files a/dotnet/extlibs/csfml-window.dll and b/dotnet/extlibs/csfml-window.dll differ
diff --git a/include/SFML/System/Resource.hpp b/include/SFML/System/Resource.hpp
index b7d165e7..cd1fbf62 100644
--- a/include/SFML/System/Resource.hpp
+++ b/include/SFML/System/Resource.hpp
@@ -28,6 +28,8 @@
 ////////////////////////////////////////////////////////////
 // Headers
 ////////////////////////////////////////////////////////////
+#include <SFML/System/Lock.hpp>
+#include <SFML/System/Mutex.hpp>
 #include <set>
 
 
@@ -111,7 +113,8 @@ private :
     ////////////////////////////////////////////////////////////
     // Member data
     ////////////////////////////////////////////////////////////
-    mutable std::set<ResourcePtr<T>*> myObservers;
+    mutable std::set<ResourcePtr<T>*> myObservers; ///< List of pointers to this resource
+    mutable Mutex                     myMutex;     ///< Mutex for preventing concurrent access to the pointer list
 };
 
 
diff --git a/include/SFML/System/Resource.inl b/include/SFML/System/Resource.inl
index c1fb5296..0582e562 100644
--- a/include/SFML/System/Resource.inl
+++ b/include/SFML/System/Resource.inl
@@ -64,6 +64,7 @@ Resource<T>& Resource<T>::operator =(const Resource<T>&)
 template <typename T>
 void Resource<T>::Connect(ResourcePtr<T>& observer) const
 {
+    sf::Lock lock(myMutex);
     myObservers.insert(&observer);
 }
 
@@ -72,5 +73,6 @@ void Resource<T>::Connect(ResourcePtr<T>& observer) const
 template <typename T>
 void Resource<T>::Disconnect(ResourcePtr<T>& observer) const
 {
+    sf::Lock lock(myMutex);
     myObservers.erase(&observer);
 }