diff --git a/toonz/sources/toonzlib/preferences.cpp b/toonz/sources/toonzlib/preferences.cpp
index 4ede0ab..2e004d5 100644
--- a/toonz/sources/toonzlib/preferences.cpp
+++ b/toonz/sources/toonzlib/preferences.cpp
@@ -230,6 +230,7 @@ Preferences::Preferences() {
   // initialize environment based on loaded preferences
   setUnits();
   setCameraUnits();
+  setUndoMemorySize();
 
   // Load level formats
   getDefaultLevelFormats(m_levelFormats);