diff --git a/poincare/src/expression.cpp b/poincare/src/expression.cpp
index 313b7bda3..6a74a2538 100644
--- a/poincare/src/expression.cpp
+++ b/poincare/src/expression.cpp
@@ -354,6 +354,9 @@ Expression Expression::deepReduce(Context & context, Preferences::AngleUnit angl
 #endif
 
   deepReduceChildren(context, angleUnit, replaceSymbols);
+  if (sSimplificationHasBeenInterrupted) {
+    return *this;
+  }
   return shallowReduce(context, angleUnit, replaceSymbols);
 }