diff --git a/src/cell.c b/src/cell.c
index 006df3e9cf1bc1b82b40350cb302d16cbe2b8213..9c6808d0afaf29d3ecd6a78198c19ffa25fa61e1 100644
--- a/src/cell.c
+++ b/src/cell.c
@@ -50,6 +50,7 @@
 #include "active.h"
 #include "atomic.h"
 #include "drift.h"
+#include "engine.h"
 #include "error.h"
 #include "gravity.h"
 #include "hydro.h"