diff --git a/stepmania/src/Actor.cpp b/stepmania/src/Actor.cpp
index 6bb5180db9..0f0dd80794 100644
--- a/stepmania/src/Actor.cpp
+++ b/stepmania/src/Actor.cpp
@@ -116,6 +116,9 @@ Actor::~Actor()
 
 Actor::Actor( const Actor &cpy )
 {
+	/* Don't copy an Actor in the middle of rendering. */
+	ASSERT( cpy.m_pTempState == NULL );
+
 #define CPY(x) x = cpy.x
 	CPY( m_sName );
 	CPY( m_pLuaInstance );
@@ -132,7 +135,6 @@ Actor::Actor( const Actor &cpy )
 		m_Tweens.push_back( new TweenStateAndInfo(*cpy.m_Tweens[i]) );
 
 	CPY( m_tempState );
-	CPY( m_pTempState );
 
 	CPY( m_bFirstUpdate );