diff --git a/toonz/sources/toonz/previewfxmanager.cpp b/toonz/sources/toonz/previewfxmanager.cpp
index ae01623..0e0e647 100644
--- a/toonz/sources/toonz/previewfxmanager.cpp
+++ b/toonz/sources/toonz/previewfxmanager.cpp
@@ -1327,6 +1327,7 @@ void PreviewFxManager::unfreeze(FlipBook *flipbook) {
 
     // Also any associated pb status
     delete flipbook->getProgressBarStatus();
+    flipbook->setProgressBarStatus(NULL);
 
     previewInstance->addFlipbook(flipbook);
     previewInstance->refreshViewRects();