diff --git a/include/osgViewer/ViewerBase b/include/osgViewer/ViewerBase
index 308c83ddc..f6126e79e 100644
--- a/include/osgViewer/ViewerBase
+++ b/include/osgViewer/ViewerBase
@@ -251,7 +251,7 @@ class OSGVIEWER_EXPORT ViewerBase : public virtual osg::Object
         
         inline void releaseContext()
         {
-            if (_currentContext.valid())
+            if (_currentContext.valid() && _currentContext->valid())
             {
                 _currentContext->releaseContext();
             }