diff --git a/Source/OpenTK/Platform/MacOS/Quartz/CoreFoundation.cs b/Source/OpenTK/Platform/MacOS/Quartz/CoreFoundation.cs
index 6b5c8818..262fd7f5 100644
--- a/Source/OpenTK/Platform/MacOS/Quartz/CoreFoundation.cs
+++ b/Source/OpenTK/Platform/MacOS/Quartz/CoreFoundation.cs
@@ -112,6 +112,9 @@ namespace OpenTK.Platform.MacOS.Carbon
         [DllImport(appServices)]
         internal static extern IntPtr CFDictionaryGetValue(IntPtr theDictionary, IntPtr theKey);
 
+        [DllImport(appServices)]
+        internal static extern IntPtr CFRetain(CFTypeRef cf);
+
         [DllImport(appServices)]
         internal static extern void CFRelease(CFTypeRef cf);