diff --git a/toonz/sources/toonz/filmstrip.cpp b/toonz/sources/toonz/filmstrip.cpp
index ea8d92f4..aa43a30d 100644
--- a/toonz/sources/toonz/filmstrip.cpp
+++ b/toonz/sources/toonz/filmstrip.cpp
@@ -855,6 +855,8 @@ void FilmstripFrames::mousePressEvent(QMouseEvent *event) {
 
   TXshSimpleLevel *sl = getLevel();
 
+  if (!sl) return;
+
   // If accessed after 1st frame on a Single Frame level
   // Block movement so we can't create new images
   if (index > 0) {