diff --git a/BasiliskII/src/extfs.cpp b/BasiliskII/src/extfs.cpp
index 99470e8f..1dc47f94 100644
--- a/BasiliskII/src/extfs.cpp
+++ b/BasiliskII/src/extfs.cpp
@@ -175,9 +175,9 @@ static uint32 next_cnid = fsUsrCNID;	// Next available CNID
 
 #if defined __APPLE__ && defined __MACH__
 struct crtimebuf {
-	unsigned long length;
+    u_int32_t length;
 	struct timespec crtime;
-};
+} __attribute__((aligned(4), packed));
 
 static uint32 do_get_creation_time(const char *path)
 {