diff --git a/code/nel/src/3d/driver/opengl/driver_opengl_window.cpp b/code/nel/src/3d/driver/opengl/driver_opengl_window.cpp
index 5bea65771..9df2a53f9 100644
--- a/code/nel/src/3d/driver/opengl/driver_opengl_window.cpp
+++ b/code/nel/src/3d/driver/opengl/driver_opengl_window.cpp
@@ -463,6 +463,7 @@ bool CDriverGL::unInit()
 	{
 		nlwarning("Can't unregister NLClass");
 	}
+	_Registered = 0;
 
 	// Restaure monitor color parameters
 	if (_NeedToRestaureGammaRamp)